U.S. patent application number 13/129578 was filed with the patent office on 2011-10-06 for optically isotropic liquid crystal medium and optical device.
This patent application is currently assigned to JNC CORPORATION. Invention is credited to Yasuhiro Haseba, Takafumi Kuninobu.
Application Number | 20110242473 13/129578 |
Document ID | / |
Family ID | 42198120 |
Filed Date | 2011-10-06 |
United States Patent
Application |
20110242473 |
Kind Code |
A1 |
Haseba; Yasuhiro ; et
al. |
October 6, 2011 |
OPTICALLY ISOTROPIC LIQUID CRYSTAL MEDIUM AND OPTICAL DEVICE
Abstract
A liquid crystal medium, which has a liquid crystal phase over a
wide temperature range, a large refractive index anisotropy, and a
large dielectric anisotropy, and exhibits an optically isotropic
liquid crystal phase, is provided. The liquid crystal medium is
characterized by containing a liquid crystal compound having four
benzene rings and a difluoromethyleneoxy group, and a chiral
reagent, and exhibiting an optically isotropic liquid crystal
phase.
Inventors: |
Haseba; Yasuhiro; (Chiba,
JP) ; Kuninobu; Takafumi; (Chiba, JP) |
Assignee: |
JNC CORPORATION
Tokyo
JP
CHISSO PETROCHEMICAL CORPORATION
Tokyo
JP
|
Family ID: |
42198120 |
Appl. No.: |
13/129578 |
Filed: |
October 27, 2009 |
PCT Filed: |
October 27, 2009 |
PCT NO: |
PCT/JP2009/068393 |
371 Date: |
May 17, 2011 |
Current U.S.
Class: |
349/139 ;
252/299.61; 252/299.66 |
Current CPC
Class: |
C09K 19/20 20130101;
C09K 19/586 20130101; C09K 2323/00 20200801; C09K 2019/0444
20130101; C09K 19/588 20130101; C09K 2019/0466 20130101; G02F
1/134363 20130101 |
Class at
Publication: |
349/139 ;
252/299.66; 252/299.61 |
International
Class: |
G02F 1/1343 20060101
G02F001/1343; C09K 19/20 20060101 C09K019/20; C09K 19/34 20060101
C09K019/34 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 19, 2008 |
JP |
2008-295842 |
Claims
1. A liquid crystal composition, comprising an achiral component T
comprising a compound of Formula (1) and a chiral reagent, and
exhibiting an optically isotropic liquid crystal phase,
##STR00104## wherein in Formula (1), R.sup.1 is hydrogen or a
C.sub.1-20 alkyl in which arbitrary --CH.sub.2-- may be substituted
with --O--, --S--, --COO--, --OCO--, --CH.dbd.CH--, --CF.dbd.CF--
or --C.ident.C--, and arbitrary hydrogen in the alkyl and the alkyl
with arbitrary --CH.sub.2-- substituted with --O--, --S--, --COO--,
--OCO--, --CH.dbd.CH--, --CF.dbd.CF--, or --C.ident.C-- may be
substituted with halogen or a C.sub.1-3 alkyl; Z.sup.1, Z.sup.2,
and Z.sup.3 are each independently a single bond, --COO--, or
--CF.sub.2O--, provided that at least one of Z.sup.1, Z.sup.2, and
Z.sup.3 is --CF.sub.2O--; and L.sup.1, L.sup.2, L.sup.3, L.sup.4,
and L.sup.5 are each independently hydrogen or fluorine; X.sup.1 is
hydrogen, halogen, --SF.sub.5, or a C.sub.1-10 alkyl in which
arbitrary --CH.sub.2-- may be substituted with --O--, --S--,
--CH.dbd.CH--, or --C.ident.C--, and arbitrary hydrogen in the
alkyl and the alkyl with arbitrary --CH.sub.2-- substituted with
--O--, --S--, --CH.dbd.CH--, or --C.ident.C-- may be substituted
with fluorine.
2. The liquid crystal composition according to claim 1, wherein in
Formula (1), R.sup.1 is a C.sub.1-20 alkyl, a C.sub.2-21 alkenyl, a
C.sub.2-21 alkynyl, a C.sub.1-19 alkoxy, a C.sub.2-20 alkenyloxy, a
C.sub.1-19 alkylthio, a C.sub.1-19 alkenylthio, or
--(CH.sub.2)v-CH.dbd.CF.sub.2, in which v is an integer of 0 or
1-19; and X.sup.1 is hydrogen, halogen, --SF.sub.5, --CH.sub.2CH,
--CHF.sub.2, --CF.sub.3, --(CH.sub.2).sub.2--F,
--CF.sub.2CH.sub.2CH, --CF.sub.2CHF.sub.2, --CH.sub.2CF.sub.3,
--CF.sub.2CF.sub.3, --(CH.sub.2).sub.3--F, --(CF.sub.2).sub.3--F,
--CF.sub.2CHFCF.sub.3, --CHFCF.sub.2CF.sub.3,
--(CH.sub.2).sub.4--F, --(CF.sub.2).sub.4--F,
--(CH.sub.2).sub.5--F, --(CF.sub.2).sub.5--F, --OCH.sub.2CH,
--OCHF.sub.2, --OCF.sub.3, --O--(CH.sub.2).sub.2--F,
--OCF.sub.2CH.sub.2CH, --OCF.sub.2CHF.sub.2, --OCH.sub.2CF.sub.3,
--O--(CH.sub.2).sub.3--F, --O--(CF.sub.2).sub.3--F,
--OCF.sub.2CHFCF.sub.3, --OCHFCF.sub.2CF.sub.3,
--O--(CH.sub.2).sub.4--F, --O--(CF.sub.2).sub.4--F,
--O--(CH.sub.2).sub.5--F, --O--(CF.sub.2).sub.5--F, --CH.dbd.CHF,
--CH.dbd.CF.sub.2, --CF.dbd.CHF, --CH.dbd.CHCH.sub.2CH,
--CH.dbd.CHCF.sub.3, --(CH.sub.2).sub.2--CH.dbd.CF.sub.2,
--CH.sub.2CH.dbd.CHCF.sub.3, or --CH.dbd.CHCF.sub.2CF.sub.3.
3. The liquid crystal composition according to claim 1, wherein in
Formula (1), Z.sup.1, Z.sup.2, and Z.sup.3 are each independently a
single bond or --CF.sub.2O--.
4. The liquid crystal composition according to claim 1, wherein
R.sup.1 is a group of any one of Formulas (CHN-1)-(CHN-19), and
R.sup.1a is hydrogen or a C.sub.1-20 alkyl, ##STR00105##
5. The liquid crystal composition according to claim 1, comprising
at least one compound selected from the group consisting of the
compounds of Formulas (1-1)-(1-3): ##STR00106## wherein in the
formulas, R.sup.1 is a group of any one of Formulas
(CHN-1)-(CHN-19), and R.sup.1a is hydrogen or a C.sub.1-20 alkyl;
L.sup.1, L.sup.2, L.sup.3, L.sup.4, and L.sup.5 are each
independently hydrogen or fluorine; and X.sup.1 is fluorine,
chlorine, --CF.sub.3, --CHF.sub.2, --CH.sub.2CH, --OCF.sub.3,
--OCHF.sub.2, --OCH.sub.2CH, --OCF.sub.2CFHCF.sub.3, or
--CH.dbd.CHCF.sub.3, ##STR00107##
6. The liquid crystal composition according to claim 5, wherein in
Formulas (1-1)-(1-3), R.sup.1 is a group of any one of Formulas
(CHN-1)-(CHN-4) and Formulas (CHN-6)-(CHN-8), and R.sup.1a is
hydrogen or a C.sub.1-20 alkyl, ##STR00108##
7. The liquid crystal composition according to claim 1, wherein the
achiral component T further comprises a compound of Formula (2):
##STR00109## wherein in Formula (2), R.sup.2 is a group of any one
of Formulas (CHN-1)-(CHN-4) and Formulas (CHN-6)-(CHN-7), R.sup.1a
is hydrogen or a C.sub.1-20 alkyl; Rings A.sup.1, A.sup.2, A.sup.3,
A.sup.4, and A.sup.5 are (RG-1)-(RG-13); Z.sup.4, Z.sup.5, Z.sup.6,
Z.sup.7, Z.sup.8, and Z.sup.9 are each independently a single bond
or a C.sub.1-4 alkylene in which arbitrary --CH.sub.2-- may be
substituted with --O--, --COO-- or --CF.sub.2O--; L.sup.6, L.sup.7
and L.sup.8 are each independently hydrogen or fluorine; X.sup.2 is
fluorine, chlorine, --CF.sub.3, --CHF.sub.2, --CH.sub.2CH,
--OCF.sub.3, --OCHF.sub.2, --OCH.sub.2CH, --OCF.sub.2CFHCF.sub.3,
or --CH.dbd.CHCF.sub.3; and l, m, n, o, and p are each
independently 0 or 1, provided that l+m+n+o+p.ltoreq.4,
##STR00110## ##STR00111##
8. The liquid crystal composition according to claim 7, wherein in
Formula (2), R.sup.2 is hydrogen or a C.sub.1-20 alkyl in which
arbitrary --CH.sub.2-- may be substituted with --O--, --S--,
--COO--, --OCO--, --CH.dbd.CH--, --CF.dbd.CF-- or --C.ident.C--,
and arbitrary hydrogen in the alkyl and the alkyl with arbitrary
--CH.sub.2-- substituted with --O--, --S--, --COO--, --OCO--,
--CH.dbd.CH--, --CF.dbd.CF-- or --C.ident.C-- may be substituted
with halogen or a C.sub.1-3 alkyl; Rings A.sup.1, A.sup.2, A.sup.3,
A.sup.4, and A.sup.5 are each independently a benzene ring, a
naphthalene ring, a thiophene ring, a piperidine ring, a
cyclohexene ring, a bicyclooctane ring, a tetrahydronaphthalene
ring or a cyclohexane ring, wherein arbitrary hydrogen in the rings
may be substituted with halogen, a C.sub.1-3 alkyl, a C.sub.1-3
alkoxy, or a C.sub.1-3 haloalkyl, --CH.sub.2-- in the rings may be
substituted with --O-- or --S--, and --CH.dbd. in the rings may be
substituted with --N.dbd.; Z.sup.4, Z.sup.5, Z.sup.6, Z.sup.7,
Z.sup.8, and Z.sup.9 are each independently a single bond or a
C.sub.1-4 alkylene in which arbitrary --CH.sub.2-- may be
substituted with --O--, --S--, --COO--, --OCO--, --CSO--, --OCS--,
--CH.dbd.CH--, --CF.dbd.CF-- or --C.ident.C--, and arbitrary
hydrogen in the alkylene or the alkylene with arbitrary
--CH.sub.2-- substituted with --O--, --S--, --COO--, --OCO--,
--CSO--, --OCS--, --CH.dbd.CH--, --CF.dbd.CF-- or --C.ident.C-- may
be substituted with halogen; L.sup.6, L.sup.7, and L.sup.8 are each
independently hydrogen or halogen; X.sup.2 is hydrogen, halogen,
--C.ident.N, --N.dbd.C.dbd.S, --C.ident.C--C.ident.N, --SF.sub.5,
or a C.sub.1-10 alkyl in which arbitrary --CH.sub.2-- may be
substituted with --O--, --S--, --CH.dbd.CH-- or --C.ident.C--, and
arbitrary hydrogen in the alkyl and the alkyl with arbitrary
--CH.sub.2-- substituted with --O--, --S--, --CH.dbd.CH-- or
--C.ident.C-- may be substituted with halogen; and l, m, n, o and p
are each independently 0 or 1, provided that
l+m+n+o+p.ltoreq.4.
9. The liquid crystal composition according to claim 8, wherein in
the compound of Formula (2), 2.ltoreq.l+m+n+o+p.ltoreq.3.
10. The liquid crystal composition according to claim 1, wherein
the achiral component T comprises only the compound of Formula
(1).
11. The liquid crystal composition according to claim 7, wherein
the achiral component T comprises only 5-95 weight percent (wt %)
of the compound of Formula (1) and 5-50 wt % of the compound of
Formula (2).
12. The liquid crystal composition according to claim 7, wherein
the achiral component T comprises 5-95 wt % of the compound of
Formula (1), 5-80 wt % of the compound of Formula (2), and 0-50 wt
% of other compounds.
13. The liquid crystal composition according to claim 7, wherein
the achiral component T comprises 5-94 wt % of the compound of
Formula (1), 5-80 wt % of the compound of Formula (2), and 1-50 wt
% of other compounds.
14. The liquid crystal composition according to claim 1, wherein
the achiral component T comprises 10-100 wt % of a compound
selected from the group consisting of Formulas (1-2A)-(1-2H) and
Formulas (1-3A)-(1-3D): ##STR00112## ##STR00113## wherein in the
formulas, R.sup.1 is a chain selected from Formulas (CHN-1),
(CHN-4), (CHN-7), (CHN-8) and (CHN-11); and X.sup.1 is fluorine,
chlorine, --CF.sub.3, --CHF.sub.2, --CH.sub.2CH, --OCF.sub.3,
--OCHF.sub.2, --OCF.sub.2CFHCF.sub.3, or --CH.dbd.CHCF.sub.3.
15. The liquid crystal composition according to claim 1, wherein
the achiral component T further comprises at least one compound
selected from the group consisting of the compounds of Formulas
(3), (4), and (5): ##STR00114## wherein in the formulas, R.sup.3 is
a C.sub.1-10 alkyl or a C.sub.2-10 alkenyl, wherein arbitrary
hydrogen in the alkyl and the alkenyl may be substituted with
fluorine, and arbitrary --CH.sub.2-- in the alkyl, the alkenyl, or
the alkyl and the alkenyl with arbitrary hydrogen substituted with
fluorine may be substituted with --O--; X.sup.3 is fluorine,
chlorine, --OCF.sub.3, --OCHF.sub.2, --CF.sub.3, --CHF.sub.2,
--CH.sub.2CH, --OCF.sub.2CHF.sub.2, or --OCF.sub.2CHFCF.sub.3;
Rings B.sup.1, B.sup.2, and B.sup.3 are each independently
1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl,
tetrahydropyran-2,5-diyl, 1,4-phenylene, naphthalene-2,6-diyl,
1,4-phenylene with arbitrary hydrogen substituted with fluorine, or
naphthalene-2,6-diyl with arbitrary hydrogen substituted with
fluorine or chlorine; in Formula (5), Ring B1 is 1,4-cyclohexylene,
1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl,
tetrahydropyran-2,5-diyl, 1,4-phenylene, naphthalene-2,6-diyl, or
naphthalene-2,6-diyl with arbitrary hydrogen substituted with
fluorine or chlorine; Z10 and Z11 are each independently
--(CH.sub.2).sub.2--, --(CH.sub.2).sub.4--, --COO--, --CF.sub.2O--,
--OCF.sub.2--, --CH.dbd.CH--, --C.ident.C--, --CH.sub.2O--, or a
single bond; and L9 and L10 are each independently hydrogen or
fluorine.
16. The liquid crystal composition according to claim 1, wherein
the achiral component T further comprises at least one compound
selected from the group consisting of the compound of Formula (6):
##STR00115## wherein in the formula, R.sup.4 is a C.sub.1-10 alkyl
or a C.sub.2-10 alkenyl, wherein arbitrary hydrogen in the alkyl
and the alkenyl may be substituted with fluorine, and arbitrary
--CH.sub.2-- in the alkyl, the alkenyl, or the alkyl and the
alkenyl with arbitrary hydrogen substituted with fluorine may be
substituted with --O--; X.sup.4 is --C.ident.N or
--C.ident.C--C.ident.N; Rings C.sup.1, C.sup.2, and C.sup.3 are
each independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene
with arbitrary hydrogen substituted with fluorine,
naphthalene-2,6-diyl, naphthalene-2,6-diyl with arbitrary hydrogen
substituted with fluorine or chlorine, 1,3-dioxane-2,5-diyl,
tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; Z.sup.12 is
--(CH.sub.2).sub.2--, --COO--, --CF.sub.2O--, --OCF.sub.2--,
--C.ident.C--, --CH.sub.2O--, or a single bond; L.sup.11 and
L.sup.12 are each independently hydrogen or fluorine; and r is 0,
1, or 2, s is 0 or 1, and r+s=0, 1 or 2.
17. The liquid crystal composition according to claim 1, wherein
the achiral component T further comprises at least one compound
selected from the group consisting of Formulas (7), (8), (9), (10),
and (11): ##STR00116## wherein in the formulas, R.sup.5 and R.sup.6
are each independently a C.sub.1-10 alkyl or a C.sub.2-10 alkenyl,
wherein arbitrary hydrogen in the alkyl and the alkenyl may be
substituted with fluorine, and arbitrary --CH.sub.2-- in the alkyl,
the alkenyl, or the alkyl and the alkenyl with arbitrary hydrogen
substituted with fluorine may be substituted with --O--; Rings
D.sup.1, D.sup.2, D.sup.3, and D.sup.4 are each independently
1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene,
1,4-phenylene with arbitrary hydrogen substituted with fluorine,
tetrahydropyran-2,5-diyl, or decahydronaphthalene-2,6-diyl;
Z.sup.13, Z.sup.14, Z.sup.15, and Z.sup.16 are each independently
--(CH.sub.2).sub.2--, --COO--, --CH.sub.2O--, --OCF.sub.2--,
--OCF.sub.2(CH.sub.2).sub.2--, or a single bond; L.sup.13 and
L.sup.14 are each independently fluorine or chlorine; and t, u, x,
y, and z are each independently 0 or 1, and u+x+y+z is 1 or 2.
18. The liquid crystal composition according to claim 1, wherein
the achiral component T further comprises at least one compound
selected from the group consisting of the compounds of Formulas
(12), (13), and (14): ##STR00117## wherein in the formulas, R.sup.7
and R.sup.8 are each independently a C.sub.1-10 alkyl or a
C.sub.2-10 alkenyl, in which arbitrary hydrogen in the alkyl and
the alkenyl may be substituted with fluorine, and arbitrary
--CH.sub.2-- in the alkyl, the alkenyl, or the alkyl and the
alkenyl with arbitrary hydrogen substituted with fluorine may be
substituted with --O--; Rings E.sup.1, E.sup.2, and E.sup.3 are
each independently 1,4-cyclohexylene, pyrimidine-2,5-diyl,
1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, or
2,5-difluoro-1,4-phenylene; Z.sup.17 and Z.sup.18 are each
independently --C.ident.C--, --COO--, --(CH.sub.2).sub.2--,
--CH.dbd.CH--, or a single bond.
19. The liquid crystal composition according to claim 15, further
comprising at least one compound selected from the group consisting
of the compound of Formula (6): ##STR00118## wherein in the
formula, R.sup.4 is a C.sub.1-10 alkyl or a C.sub.2-10 alkenyl,
wherein arbitrary hydrogen in the alkyl and the alkenyl may be
substituted with fluorine, and arbitrary --CH.sub.2-- in the alkyl,
the alkenyl, or the alkyl and the alkenyl with arbitrary hydrogen
substituted with fluorine may be substituted with --O--; X.sup.4 is
--C.ident.N or --C.ident.C--C.ident.N; Rings C.sup.1, C.sup.2, and
C.sup.3 are each independently 1,4-cyclohexylene, 1,4-phenylene,
1,4-phenylene with arbitrary hydrogen substituted with fluorine,
naphthalene-2,6-diyl, naphthalene-2,6-diyl with arbitrary hydrogen
substituted with fluorine or chlorine, 1,3-dioxane-2,5-diyl,
tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; Z.sup.12 is
--(CH.sub.2).sub.2--, --COO--, --CF.sub.2O--, --OCF.sub.2--,
--C.ident.C--, --CH.sub.2O--, or a single bond; L.sup.11 and
L.sup.12 are each independently hydrogen or fluorine; and r is 0,
1, or 2, s is 0 or 1, and r+s=0, 1 or 2.
20. The liquid crystal composition according to claim 15, further
comprising at least one compound selected from the group consisting
of the compounds of Formula (12), (13), and (14): ##STR00119##
wherein in the formulas, R.sup.7 and R.sup.8 are each independently
a C.sub.1-10 alkyl or a C.sub.2-10 alkenyl, in which arbitrary
hydrogen in the alkyl and the alkenyl may be substituted with
fluorine, and arbitrary --CH.sub.2-- in the alkyl, the alkenyl, or
the alkyl and the alkenyl with arbitrary hydrogen substituted with
fluorine may be substituted with --O--; Rings E.sup.1, E.sup.2, and
E.sup.3 are each independently 1,4-cyclohexylene,
pyrimidine-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene,
3-fluoro-1,4-phenylene, or 2,5-difluoro-1,4-phenylene; Z.sup.17 and
Z.sup.18 are each independently --C.ident.C--, --COO--,
--(CH.sub.2--, --CH.dbd.CH--, or a single bond.
21. The liquid crystal composition according to claim 16, further
comprising at least one compound selected from the group consisting
of the compounds of Formulas (12), (13), and (14): ##STR00120##
wherein in the formulas, R.sup.7 and R.sup.8 are each independently
a C.sub.1-10 alkyl or a C.sub.2-10 alkenyl, in which arbitrary
hydrogen in the alkyl and the alkenyl may be substituted with
fluorine, and arbitrary --CH.sub.2-- in the alkyl, the alkenyl, or
the alkyl and the alkenyl with arbitrary hydrogen substituted with
fluorine may be substituted with --O--; Rings E.sup.1, E.sup.2, and
E.sup.3 are each independently 1,4-cyclohexylene,
pyrimidine-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene,
3-fluoro-1,4-phenylene, or 2,5-difluoro-1,4-phenylene; Z.sup.17 and
Z.sup.18 are each independently --C.ident.C--, --COO--,
--(CH.sub.2).sub.2--, --CH.dbd.CH--, or a single bond.
22. The liquid crystal composition according to claim 17, further
comprising at least one compound selected from the group consisting
of the compounds of Formulas (12), (13), and (14): ##STR00121##
wherein in the formulas, R.sup.7 and R.sup.8 are each independently
a C.sub.1-10 alkyl or a C.sub.2-10 alkenyl, in which arbitrary
hydrogen in the alkyl and the alkenyl may be substituted with
fluorine, and arbitrary --CH.sub.2-- in the alkyl, the alkenyl, or
the alkyl and the alkenyl with arbitrary hydrogen substituted with
fluorine may be substituted with --O--; Rings E.sup.1, E.sup.2, and
E.sup.3 are each independently 1,4-cyclohexylene,
pyrimidine-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene,
3-fluoro-1,4-phenylene, or 2,5-difluoro-1,4-phenylene; Z.sup.17 and
Z.sup.18 are each independently --C.ident.C--, --COO--,
--(CH.sub.2).sub.2--, --CH.dbd.CH--, or a single bond.
23. The liquid crystal composition according to claim 1, wherein
the achiral component T further comprises at least one compound
selected from the group consisting of the compound of Formulas
(15), (16), (17), and (18): ##STR00122## wherein in the formulas,
R.sup.9 is a C.sub.1-10 alkyl, a C.sub.2-10 alkenyl, or a
C.sub.2-10 alkynyl, wherein arbitrary hydrogen in the alkyl, the
alkenyl and the alkynyl may be substituted with fluorine, and
arbitrary --CH.sub.2-- in the alkyl, the alkenyl, the alkynyl, or
the alkyl, the alkenyl and the alkynyl with arbitrary hydrogen
substituted with fluorine may be substituted with --O--; X.sup.5 is
fluorine, chlorine, --SF.sub.5, --OCF.sub.3, --OCHF.sub.2,
--CF.sub.3, --CHF.sub.2, --CH.sub.2CH, --OCF.sub.2CHF.sub.2, or
--OCF.sub.2CHFCF.sub.3; Rings F.sup.1, F.sup.2, F.sup.3, and
F.sup.4 are each independently 1,4-cyclohexylene,
1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl,
tetrahydropyran-2,5-diyl, 1,4-phenylene, naphthalene-2,6-diyl,
1,4-phenylene with arbitrary hydrogen substituted with fluorine or
chlorine, or naphthalene-2,6-diyl with arbitrary hydrogen
substituted with fluorine or chlorine; in Formulas (17), Ring
F.sup.1 is 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl,
pyrimidine-2,5-diyl, tetrahydropyran-2,5-diyl, 1,4-phenylene,
naphthalene-2,6-diyl, or naphthalene-2,6-diyl with arbitrary
hydrogen substituted with fluorine or chlorine; Z.sup.19, Z.sup.20,
and Z.sup.21 are each independently --(CH.sub.2).sub.2--,
--(CH.sub.2).sub.4--, --COO--, --CF.sub.2O--, --OCF.sub.2--,
--CH.dbd.CH--, --C.ident.C--, --CH.sub.2O--, or a single bond; and
L.sup.15 and L.sup.16 are each independently hydrogen or
fluorine.
24. The liquid crystal composition according to claim 1, wherein
the achiral component T further comprises at least one compound
selected from the group consisting of the compound of Formula (19):
##STR00123## wherein in the formulas, R.sup.10 is a C.sub.1-10
alkyl, a C.sub.2-10 alkenyl, or a C.sub.2-10 alkynyl, wherein
arbitrary hydrogen in the alkyl, the alkenyl and the alkynyl may be
substituted with fluorine, and arbitrary --CH.sub.2-- in the alkyl,
the alkenyl, the alkynyl, or the alkyl, the alkenyl and the alkynyl
with arbitrary hydrogen substituted with fluorine may be
substituted with --O--; X.sup.6 is --C.ident.N, --N.dbd.C.dbd.S, or
--C.ident.C--C.ident.N; Rings G.sup.1, G.sup.2, and G.sup.3 are
each independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene
with arbitrary hydrogen substituted with fluorine or chlorine,
naphthalene-2,6-diyl, naphthalene-2,6-diyl with arbitrary hydrogen
substituted with fluorine or chlorine, 1,3-dioxane-2,5-diyl,
tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; Z.sup.22 is
--(CH.sub.2).sub.2--, --COO--, --CF.sub.2O--, --OCF.sub.2--,
--C.ident.C--, --CH.sub.2O--, or a single bond; L.sup.17 and
L.sup.18 are each independently hydrogen or fluorine; and aa is 0,
1 or 2, ab is 0 or 1, and aa+ab is 0, 1 or 2.
25. The liquid crystal composition according to claim 1, comprising
at least one antioxidant and/or UV absorbent.
26. The liquid crystal composition according to claim 1, wherein
the optically isotropic liquid crystal phase does not exhibit two
or more colors of diffracted light.
27. The liquid crystal composition according to claim 1, wherein
the optically isotropic liquid crystal phase exhibits two or more
colors of diffracted light.
28. The liquid crystal composition according to claim 26, obtained
by adding the chiral reagent into a composition having a
temperature difference of 3.degree. C.-150.degree. C. between an
upper-limit temperature and a lower-limit temperature of
co-existence of a chiral nematic phase and a non-liquid crystal
isotropic phase.
29. The liquid crystal composition according to claim 26, obtained
by adding the chiral reagent into a composition having a
temperature difference of 5.degree. C.-150.degree. C. between an
upper-limit temperature and a lower-limit temperature of
co-existence of a chiral nematic phase and a non-liquid crystal
isotropic phase.
30. The liquid crystal composition according to claim 26, obtained
by adding the chiral reagent into a composition having a
temperature difference of 3.degree. C.-150.degree. C. between an
upper-limit temperature and a lower-limit temperature of
co-existence of a nematic phase and a non-liquid crystal isotropic
phase.
31. The liquid crystal composition according to claim 1, wherein a
content of the chiral reagent is 1-40 wt % based on the total
weight of the liquid crystal composition.
32. The liquid crystal composition according to claim 1, wherein a
content of the chiral reagent is 5-15 wt % based on the total
weight of the liquid crystal composition.
33. The liquid crystal composition according to claim 31,
exhibiting a chiral nematic phase at any temperature in the range
of 70.degree. C. to -20.degree. C., and having a helical pitch of
700 nm or less within at least a part of the temperature range.
34. The liquid crystal composition according to claim 31, wherein
the chiral reagent comprises at least one compound selected from
the group consisting of the compounds of Formulas (K1)-(K5):
##STR00124## wherein in Formulas (K1)-(K5), R.sup.K is each
independently hydrogen, halogen, --C.ident.N, --N.dbd.C.dbd.O,
--N.dbd.C.dbd.S, or a C.sub.1-20 alkyl in which arbitrary
--CH.sub.2-- may be substituted substituted with --O--, --S--,
--COO--, --OCO--, --CH.dbd.CH--, --CF.dbd.CF-- or --C.ident.C--,
arbitrary hydrogen in the alkyl may be substituted with halogen,
and additionally, a terminal --CH.sub.3 may be substituted with:
##STR00125## A is each independently an aromatic or non-aromatic 3-
to 8-membered ring, or a fused ring having 9 or more carbon atoms,
wherein arbitrary hydrogen in the rings may be substituted with
halogen, a C.sub.1-3 alkyl or haloalkyl, --CH.sub.2-- in the rings
may be substituted with --O--, --S--, or --NH--, and --CH.dbd. in
the rings may be substituted with --N.dbd.; B is each independently
hydrogen, halogen, a C.sub.1-3 alkyl, a C.sub.1-3 haloalkyl, an
aromatic or non-aromatic 3- to 8-membered ring, or a fused ring
having 9 or more carbon atoms, wherein arbitrary hydrogen in the
rings may be substituted with halogen, a C.sub.1-3 alkyl or
haloalkyl, --CH.sub.2-- in the rings may be substituted with --O--,
--S-- or --NH--, and --CH.dbd. in the rings may be substituted with
--N.dbd.; Z is each independently a single bond, or a C.sub.1-8
alkylene in which arbitrary --CH.sub.2-- may be substituted with
--O--, --S--, --COO--, --OCO--, --CSO--, --OCS--, --N.dbd.N--,
--CH.dbd.N--, --N.dbd.CH--, --CH.dbd.CH--, --CF.dbd.CF--, or
--C.ident.C--, and arbitrary hydrogen in the alkylene may be
substituted with halogen; X is a single bond, --COO--, --OCO--,
--CH.sub.2O--, --OCH.sub.2--, --CF.sub.2O--, --OCF.sub.2--, or
--CH.sub.2CH.sub.2--; and mK is an integer of 1-4.
35. The liquid crystal composition according to claim 31, wherein
the chiral reagent comprises at least one compound selected from
the group consisting of the compounds of Formulas (K2-1)-(K2-8),
Formulas (K4-1)-(K4-6), and Formulas (K5-1)-(K5-3): ##STR00126##
##STR00127## wherein in the formulas, R.sup.K is each independently
a C.sub.3-10 alkyl, wherein --CH.sub.2-- adjacent to a ring in the
alkyl may be substituted with --O--, and arbitrary --CH.sub.2-- in
the alkyl may be substituted with --CH.dbd.CH--.
36. A mixture, comprising the liquid crystal composition according
to claim 1 and a polymerizable monomer.
37. The mixture according to claim 36, wherein the polymerizable
monomer is a photopolymerizable monomer or a thermal-polymerizable
monomer.
38. A polymer/liquid crystal composite material, obtained by
polymerizing the mixture comprising the liquid crystal composition
according to claim 1 and a polymerizable monomer, for use in a
device driven in an optically isotropic liquid crystal phase.
39. The polymer/liquid crystal composite material according to
claim 38, obtained by polymerizing the mixture comprising the
liquid crystal composition according to claim 1 and a polymerizable
monomer in a non-liquid crystal isotropic phase or an optically
isotropic liquid crystal phase.
40. The polymer/liquid crystal composite material according to
claim 38, wherein the polymer in the polymer/liquid crystal
composite material has a mesogen moiety.
41. The polymer/liquid crystal composite material according to
claim 38, wherein the polymer in the polymer/liquid crystal
composite material has a cross-linked structure.
42. The polymer/liquid crystal composite material according to
claim 38, wherein a content of the liquid crystal composition is
60-99 wt %, and a content of the polymer is 1-40 wt %.
43. An optical device, comprising a liquid crystal medium disposed
between substrates having electrodes disposed on either or both
surfaces thereof and an electric field-applying means for applying
an electric field to the liquid crystal medium via the electrodes,
wherein the liquid crystal medium is the liquid crystal composition
according to claim 1, wherein a content of the chiral reagent is
1-40 wt % based on the total weight of the liquid crystal
composition or the polymer/liquid crystal composite material
obtained by polymerizing the mixture comprising the liquid crystal
composition according to claim 1 and a polymerizable monomer, for
use in a device driven in an optically isotropic liquid crystal
phase.
44. An optical device, comprising a set of substrates having
electrodes disposed on either or both surfaces thereof, at least
one of which being transparent, a liquid crystal medium disposed
between the substrates, a polarizer disposed outside of the
substrates, and an electric field-applying means for applying an
electric field to the liquid crystal medium via the electrodes,
wherein the liquid crystal medium is the liquid crystal composition
according to claim 1, wherein a content of the chiral reagent is
1-40 wt % based on the total weight of the liquid crystal
composition or the polymer/liquid crystal composite material
obtained by polymerizing the mixture comprising the liquid crystal
composition according to claim 1 and a polymerizable monomer, for
use in a device driven in an optically isotropic liquid crystal
phase.
45. The optical device according to claim 43, wherein on at least
one of the set of substrates, the electrodes are configured in a
manner such that an electric field is applied in at least two
directions.
46. The optical device according to claim 43, wherein on one or two
of the set of substrates disposed in parallel with each other, the
electrodes are configured in a manner such that an electric field
is applied in at least two directions.
47. The optical device according to claim 43, wherein the
electrodes are disposed in a matrix form to form pixel electrodes,
and each pixel is provided with an active element being a thin film
transistor (TFT).
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to a liquid crystal
medium useful as a material for an optical device, and in
particular, to a liquid crystal medium having a liquid crystal
phase over a wide temperature range, and having a large dielectric
anisotropy and a large refractive index anisotropy. The present
invention further relates to an optical device using the liquid
crystal medium, and in particular, to an optical device that can be
used in a wide temperature range and driven at a low voltage, and
is capable of achieving a high-speed electro-optical response. The
so-called optical device refers to various devices using
electro-optic effect to achieve the function of optical modulation
or optical switching, for example, display devices (LCD devices)
and optical modulation devices used in optical communication
systems, optical information processing or various sensor
systems.
[0003] 2. Description of Related Art
[0004] Liquid crystal display (LCD) devices utilizing liquid
crystal compositions are widely used as the display for clocks,
calculators, word processors, and so on. These LCD devices utilize
the refractive index anisotropy and dielectric anisotropy and the
like of liquid crystal compounds. The operation modes of the LCD
devices are known and mainly include phase change (PC), twisted
nematic (TN), super twisted nematic (STN), bistable twisted nematic
(BTN), electrically controlled birefringence (ECB), optically
compensated bend (OCB), in-plane switching (IPS), and vertical
alignment (VA) and so on, which utilize one or more polarizers for
display. Moreover, in recent years, more attention has been paid to
the mode where an electric field is applied to an optically
isotropic liquid crystal phase to induce electric birefringence
(Patent References 1-9, and Non-patent References 1-3).
[0005] Moreover, wavelength variable filters, wavefront control
devices, liquid-crystal lenses, aberration correction devices,
aperture control devices, and optical head devices and the like
that utilize the electric birefringence in a blue phase as one of
the optically isotropic liquid crystal phases have been proposed
(Patent References 10-12).
[0006] According to the driving mode, the devices can be classified
into passive matrix (PM) and active matrix (AM) types. The PM type
is further classified into static type and multiplex type, and the
AM type is further classified into thin film transistor (TFT) type
and metal-insulator-metal (MIM) type.
[0007] Such LCD devices contain a liquid crystal composition having
suitable physical properties. In order to improve the
characteristics of an LCD device, the liquid crystal composition
preferably has suitable physical properties. A liquid crystal
compound as a component of the liquid crystal composition requires
to have the following general properties:
[0008] (1) stable chemical properties and stable physical
properties;
[0009] (2) a high clearing point (i.e., phase transition
temperature from the liquid crystal phase to the isotropic
phase);
[0010] (3) a low lower-limit temperature of a liquid crystal phase
(i.e., optically isotropic liquid crystal phase, such as nematic
phase, cholesteric phase, smectic phase, and blue phase);
[0011] (4) excellent compatibility with other liquid crystal
compounds;
[0012] (5) a suitable dielectric anisotropy; and
[0013] (6) a suitable refractive index anisotropy.
[0014] Particularly, for an optically isotropic liquid crystal
phase, a liquid crystal compound having a large dielectric
anisotropy and a large refractive index anisotropy is preferred, in
view of lowering the driving voltage.
[0015] When a liquid crystal composition containing a liquid
crystal compound having stable chemical and physical properties as
described in (1) is used in an LCD device, the voltage holding
ratio is improved.
[0016] Further, a liquid crystal composition containing a liquid
crystal compound having a high clearing point or a low lower-limit
temperature of a liquid crystal phase as described in (2) and (3),
may have an expanded temperature range of a nematic phase or
optically isotropic liquid crystal phase, and thus can be used in a
display device in a wider temperature range. A liquid crystal
composition is generally prepared by mixing a liquid crystal
compound with a number of other liquid crystal compounds, so as to
exhibit better properties that are difficult to develop by a single
liquid crystal compound. Therefore, a liquid crystal compound
having good compatibility with other liquid crystal compounds as
described in (4) is preferably used in an LCD device. In recent
years, LCD devices with superior properties, especially display
performance such as contrast, display capacity, and response time,
are required. In addition, as for the liquid crystal material that
is being used, a liquid crystal composition having a low driving
voltage is required. Furthermore, in order to drive an optical
device that is driven in an optically isotropic liquid crystal
phase with a low voltage, a liquid crystal compound with a large
dielectric anisotropy and a large refractive index anisotropy is
preferred.
[0017] As for the optically isotropic polymer/liquid crystal
composite materials disclosed in Patent References 1-3 and
Non-patent References 1-3, high voltages for device operation are
required. Although optically isotropic liquid crystal compositions
and polymer/liquid crystal composite materials, which are expected
to have an operation voltage lower than the voltages as described
above, are disclosed in Patent References 4-9, an optically
isotropic liquid crystal composition and a polymer/liquid crystal
composite material of the present invention were not disclosed.
REFERENCES IN PRIOR ART
Patent References
[0018] [Patent Reference 1] Japanese Patent Publication No.
2003-327966 [0019] [Patent Reference 2] International Publication
No. 2005/90520 pamphlet [0020] [Patent Reference 3] Japanese Patent
Publication No. 2005-336477 [0021] [Patent Reference 4] Japanese
Patent Publication No. 2006-89622 [0022] [Patent Reference 5]
Japanese Patent Publication No. 2006-299084 [0023] [Patent
Reference 6] Japanese Patent Publication No. 2006-506477 [0024]
[Patent Reference 7] Japanese Patent Publication No. 2006-506515
[0025] [Patent Reference 8] International Publication No.
2006/063662 pamphlet [0026] [Patent Reference 9] Japanese Patent
Publication No. 2006-225655 [0027] [Patent Reference 10] Japanese
Patent Publication No. 2005-157109 [0028] [Patent Reference 11]
International Publication No. 2005/80529 pamphlet [0029] [Patent
Reference 12] Japanese Patent Publication No. 2006-127707
Non-Patent References
[0029] [0030] [Non-patent Reference 1] Nature Materials, 1, 64,
(2002) [0031] [Non-patent Reference 2] Adv. Mater., 17, 96, (2005)
[0032] [Non-patent Reference 3] Journal of the SID, 14, 551,
(2006)
SUMMARY OF THE INVENTION
[0033] The present invention is directed to a liquid crystal
medium, which is stable to heat and light, has a liquid crystal
phase over a wide temperature range, a large refractive index
anisotropy and a large dielectric anisotropy, and exhibits an
optically isotropic liquid crystal phase. The present invention is
further directed to various optical devices containing the liquid
crystal medium, which can be used over a wide temperature range,
and have a short response time, a high contrast, and a low driving
voltage.
[0034] The inventors identifies that, in order to have a liquid
crystal phase over a practical temperature range in one aspect and
exhibit a large refractive index anisotropy and dielectric
anisotropy in another aspect, a liquid crystal composition having a
compound of Formula (1) with four benzene rings and at least one
linking group --CF.sub.2O-- as a main component and exhibiting an
optically isotropic liquid crystal phase is suitable. The present
invention provides a liquid crystal medium (liquid crystal
composition or polymer/liquid crystal composite) and an optical
device containing the liquid crystal medium.
[0035] [1] A liquid crystal composition, containing an achiral
component T including a compound of Formula (1), and a chiral
reagent, and exhibiting an optically isotropic liquid crystal
phase.
##STR00001##
[0036] (in Formula (1), R.sup.1 is hydrogen or a C.sub.1-20 alkyl,
wherein arbitrary --CH.sub.2-- in the alkyl may be substituted with
--O--, --S--, --COO--, --OCO--, --CH.dbd.CH--, --CF.dbd.CF-- or
--C.ident.C--, and arbitrary hydrogen in the alkyl and the alkyl
with arbitrary --CH.sub.2-- substituted with --O--, --S--, --COO--,
--OCO--, --CH.dbd.CH--, --CF.dbd.CF--, or --C.ident.C-- may be
substituted with halogen or a C.sub.1-3 alkyl; Z.sup.1, Z.sup.2,
and Z.sup.3 are each independently a single bond, --COO--, or
--CF.sub.2O--, provided that at least one of Z.sup.1, Z.sup.2, and
Z.sup.3 is --CF.sub.2O--; and L.sup.1, L.sup.2, L.sup.3, L.sup.4,
and L.sup.5 are each independently hydrogen or fluorine; X.sup.1 is
hydrogen, halogen, --SF.sub.5, or a C.sub.1-10 alkyl, wherein
arbitrary --CH.sub.2-- in the alkyl may be substituted with --O--,
--S--, --CH.dbd.CH--, or --C.ident.C--, and arbitrary hydrogen in
the alkyl and the alkyl with arbitrary --CH.sub.2-- substituted
with --O--, --S--, --COO--, --OCO--, --CH.dbd.CH--, --CF.dbd.CF--,
or --C.ident.C-- may be substituted with fluorine.)
[0037] [2] The liquid crystal composition according to item 1, in
which in Formula (1), R.sup.1 is a C.sub.1-20 alkyl, a C.sub.2-21
alkenyl, a C.sub.2-21 alkynyl, a C.sub.1-19 alkoxy, a C.sub.2-20
alkenyloxy, a C.sub.1-19 alkylthio, a C.sub.1-19 alkenylthio, or
--(CH.sub.2)v-CH.dbd.CF.sub.2, in which v is an integer of 0 or
1-19; and X.sup.1 is hydrogen, halogen, --SF.sub.5, --CH.sub.2CH,
--CHF.sub.2, --CF.sub.3, --(CH.sub.2).sub.2--F,
--CF.sub.2CH.sub.2CH, --CF.sub.2CHF.sub.2, --CH.sub.2CF.sub.3,
--CF.sub.2CF.sub.3, --(CH.sub.2).sub.3--F, --(CF.sub.2).sub.3--F,
--CF.sub.2CHFCF.sub.3, --CHFCF.sub.2CF.sub.3,
--(CH.sub.2).sub.4--F, --(CF.sub.2).sub.4--F,
--(CH.sub.2).sub.5--F, --(CF.sub.2).sub.5--F, --OCH.sub.2CH,
--OCHF.sub.2, --OCF.sub.3, --O--(CH.sub.2).sub.2--F,
--OCF.sub.2CH.sub.2CH, --OCF.sub.2CHF.sub.2, --OCH.sub.2CF.sub.3,
--O--(CH.sub.2).sub.3--F, --O--(CF.sub.2).sub.3--F,
--OCF.sub.2CHFCF.sub.3, --OCHFCF.sub.2CF.sub.3,
--O--(CH.sub.2).sub.4--F, --O--(CF.sub.2).sub.4--F,
--O--(CH.sub.2).sub.5--F, --O--(CF.sub.2).sub.5--F, --CH.dbd.CHF,
--CH.dbd.CF.sub.2, --CF.dbd.CHF, --CH.dbd.CHCH.sub.2CH,
--CH.dbd.CHCF.sub.3, --(CH.sub.2).sub.2--CH.dbd.CF.sub.2,
--CH.sub.2CH.dbd.CHCF.sub.3, or --CH.dbd.CHCF.sub.2CF.sub.3.
[0038] [3] The liquid crystal composition according to item 1 or 2,
in which in Formulas (1), Z.sup.1, Z.sup.2, and Z.sup.3 are each
independently a single bond or --CF.sub.2O--.
[0039] [4] The liquid crystal composition according to any one of
items 1 to 3, in which R.sup.1 is a group of any one of Formulas
(CHN-1)-(CHN-19), and R.sup.1a is hydrogen or a C.sub.1-20
alkyl.
##STR00002##
[0040] [5] The liquid crystal composition according to item 1,
containing at least one compound selected from the group consisting
of the compounds of Formulas (1-1)-(1-3).
##STR00003##
[0041] (in the formulas, R.sup.1 is a group of any one of Formulas
(CHN-1)-(CHN-19), and R.sup.1a is hydrogen or a C.sub.1-20 alkyl;
L.sup.1, L.sup.2, L.sup.3, L.sup.4, and L.sup.5 are each
independently hydrogen or fluorine; and X.sup.1 is fluorine,
chlorine, --CF.sub.3, --CHF.sub.2, --CH.sub.2CH, --OCF.sub.3,
--OCHF.sub.2, --OCH.sub.2CH, --OCF.sub.2CFHCF.sub.3, or
--CH.dbd.CHCF.sub.3.)
##STR00004##
[0042] [6] The liquid crystal composition according to item 5, in
which in Formulas (1-1)-(1-3), R.sup.1 is a group of any one of
Formulas (CHN-1)-(CHN-4) and Formulas (CHN-6)-(CHN-8), and R.sup.1a
is hydrogen or a C.sub.1-20 alkyl.
##STR00005##
[0043] [7] The liquid crystal composition according to any one of
items 1 to 6, in which the achiral component T further contains a
compound of Formula (2).
##STR00006##
[0044] (in Formula (2), R.sup.2 is a group of any one of Formulas
(CHN-1)-(CHN-4) and Formulas (CHN-6)-(CHN-7), R.sup.1a is hydrogen
or a C.sub.1-20 alkyl; Rings A.sup.1, A.sup.2, A.sup.3, A.sup.4,
and A.sup.5 are (RG-1)-(RG-13); Z.sup.4, Z.sup.5, Z.sup.6, Z.sup.7,
Z.sup.8, and Z.sup.9 are each independently a single bond or a
C.sub.1-4 alkylene, wherein arbitrary --CH.sub.2-- in the alkylene
may be substituted with --O--, --COO-- or --CF.sub.2O--; L.sup.6,
L.sup.7 and L.sup.8 are each independently hydrogen or fluorine;
X.sup.2 is fluorine, chlorine, CF.sub.3, --CHF.sub.2, --CH.sub.2CH,
--OCF.sub.3, --OCHF.sub.2, --OCH.sub.2CH, --OCF.sub.2CFHCF.sub.3,
or --CH.dbd.CHCF.sub.3; and l, m, n, o, and p are each
independently 0 or 1, provided that l+m+n+o+p.ltoreq.4.)
##STR00007## ##STR00008##
[0045] [8] The liquid crystal composition according to item 7, in
which in Formula (2), R.sup.2 is hydrogen or a C.sub.1-20 alkyl,
wherein arbitrary --CH.sub.2-- in alkyl may be substituted with
--O--, --S--, --COO--, --OCO--, --CH.dbd.CH--, --CF.dbd.CF-- or
--C.ident.C--, and any hydrogen in the alkyl and the alkyl with
arbitrary --CH.sub.2-- substituted with --O--, --S--, --COO--,
--OCO--, --CH.dbd.CH--, --CF.dbd.CF-- or --C.ident.C-- may be
substituted with halogen or a C.sub.1-3 alkyl; Rings A.sup.1,
A.sup.2, A.sup.3, A.sup.4, and A.sup.5 are each independently a
benzene ring, a naphthalene ring, a thiophene ring, a piperidine
ring, a cyclohexene ring, a bicyclooctane ring, a
tetrahydronaphthalene ring or a cyclohexane ring, wherein arbitrary
hydrogen in the rings may be substituted with halogen, a C.sub.1-3
alkyl, a C.sub.1-3 alkoxy, or a C.sub.1-3 haloalkyl, --CH.sub.2--
in the rings may be substituted with --O-- or --S--, and --CH.dbd.
in the rings may be substituted with --N.dbd.; Z.sup.4, Z.sup.5,
Z.sup.6, Z.sup.7, Z.sup.8, and Z.sup.9 are each independently a
single bond or a C.sub.1-4 alkylene, wherein arbitrary --CH.sub.2--
in the alkylene may be substituted with --O--, --S--, --COO--,
--OCO--, --CSO--, --OCS--, --CH.dbd.CH--, --CF.dbd.CF-- or
--C.ident.C--, and arbitrary hydrogen in the alkylene or the
alkylene with arbitrary --CH.sub.2-- substituted with --O--, --S--,
--COO--, --OCO--, --CSO--, --OCS--, --CH.dbd.CH--, --CF.dbd.CF-- or
--C.ident.C-- may be substituted with halogen; L.sup.6, L.sup.7,
and L.sup.8 are each independently hydrogen or halogen; X.sup.2 is
hydrogen, halogen, --C.ident.N, --N.dbd.C.dbd.S,
--C.ident.C--C.ident.N, --SF.sub.5, or a C.sub.1-10 alkyl, wherein
arbitrary --CH.sub.2-- in the alkyl may be substituted with --O--,
--S--, --CH.dbd.CH-- or --C.ident.C--, and arbitrary hydrogen in
the alkyl and the alkyl with arbitrary --CH.sub.2-- substituted
with --O--, --S--, --CH.dbd.CH-- or --C.ident.C-- may be
substituted with halogen; and l, m, n, o and p are each
independently 0 or 1, provided that l+m+n+o+p.ltoreq.4.
[0046] [9] The liquid crystal composition according to item 8, in
which in the compound of Formula (2),
2.ltoreq.1+m+n+o+p.ltoreq.3.
[0047] [10] The liquid crystal composition according to any one of
items 1 to 6, in which the achiral component T contains only the
compound of Formula (1).
[0048] [11] The liquid crystal composition according to any one of
items 1 to 9, in which the achiral component T contains only 5-95
weight percent (wt %) of the compound of Formula (1) and 5-50 wt %
of the compound of Formula (2).
[0049] [12] The liquid crystal composition according to any one of
items 1 to 9, in which the achiral component T contains 5-95 wt %
of the compound of Formula (1), 5-80 wt % of the compound of
Formula (2), and 0-50 wt % of other compounds.
[0050] [13] The liquid crystal composition according to any one of
items 1 to 9, in which the achiral component T contains 5-94 wt %
of the compound of Formula (1), 5-80 wt % of the compound of
Formula (2), and 1-50 wt % of other compounds.
[0051] [14] The liquid crystal composition according to any one of
items 1 to 13, in which the achiral component T contains 10-100 wt
% of a compound selected from the group consisting of compounds of
Formulas (1-2A)-(1-2H) and Formulas (1-3A)-(1-3D).
##STR00009## ##STR00010##
[0052] (in the formulas, R.sup.1 is a chain selected from Formulas
(CHN-1), (CHN-4), (CHN-7), (CHN-8) and (CHN-11); and X.sup.1 is
fluorine, chlorine, --CF.sub.3, --CHF.sub.2, --CH.sub.2CH,
--OCF.sub.3, --OCHF.sub.2, --OCF.sub.2CFHCF.sub.3, or
--CH.dbd.CHCF.sub.3.)
[0053] [15] The liquid crystal composition according to any one of
items 1 to 14, in which the achiral component T further contains at
least one compound selected from the group consisting of the
compounds of Formulas (3), (4), and (5).
##STR00011##
[0054] (in the formulas, R.sup.3 is a C.sub.1-10 alkyl or a
C.sub.2-10 alkenyl, wherein arbitrary hydrogen in the alkyl and the
alkenyl may be substituted with fluorine, and arbitrary
--CH.sub.2-- in the alkyl, the alkenyl, or the alkyl and the
alkenyl with arbitrary hydrogen substituted with fluorine may be
substituted with --O--; X.sup.3 is fluorine, chlorine, --OCF.sub.3,
--OCHF.sub.2, --CF.sub.3, --CHF.sub.2, --CH.sub.2CH,
--OCF.sub.2CHF.sub.2, or --OCF.sub.2CHFCF.sub.3; Rings B.sup.1,
B.sup.2, and B.sup.3 are each independently 1,4-cyclohexylene,
1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl,
tetrahydropyran-2,5-diyl, 1,4-phenylene, naphthalene-2,6-diyl,
1,4-phenylene with arbitrary hydrogen substituted with fluorine, or
naphthalene-2,6-diyl with arbitrary hydrogen substituted with
fluorine or chlorine; in Formula (5), Ring B.sup.1 is
1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl,
tetrahydropyran-2,5-diyl, 1,4-phenylene, naphthalene-2,6-diyl, or
naphthalene-2,6-diyl with arbitrary hydrogen substituted with
fluorine or chlorine; Z.sup.10 and Z.sup.11 are each independently
--(CH.sub.2).sub.2--, --(CH.sub.2).sub.4--, --COO--, --CF.sub.2O--,
--OCF.sub.2--, --CH.dbd.CH--, --C.ident.C--, --CH.sub.2O--, or a
single bond; and L.sup.9 and L.sup.10 are each independently
hydrogen or fluorine.)
[0055] [16] The liquid crystal composition according to any one of
items 1 to 14, in which the achiral component T further contains at
least one compound selected from the group consisting of the
compound of Formula (6).
##STR00012##
[0056] (in the formula, R.sup.4 is a C.sub.1-10 alkyl or a
C.sub.2-10 alkenyl, wherein arbitrary hydrogen in the alkyl and the
alkenyl may be substituted with fluorine, and arbitrary
--CH.sub.2-- in the alkyl, the alkenyl, or the alkyl and the
alkenyl with arbitrary hydrogen substituted with fluorine may be
substituted with --O--; X.sup.4 is --C.ident.N or --C C--C.ident.N;
Rings C.sup.1, C.sup.2, and C.sup.3 are each independently
1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene with arbitrary
hydrogen substituted with fluorine, naphthalene-2,6-diyl,
naphthalene-2,6-diyl with arbitrary hydrogen substituted with
fluorine or chlorine, 1,3-dioxane-2,5-diyl,
tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; Z.sup.12 is
--(CH.sub.2).sub.2--, --COO--, --CF.sub.2O--, --OCF.sub.2--,
--C.ident.C--, --CH.sub.2O--, or a single bond; L.sup.11 and
L.sup.12 are each independently hydrogen or fluorine; and r is 0,
1, or 2, s is 0 or 1, and r+s=0, 1 or 2.)
[0057] [17] The liquid crystal composition according to any one of
items 1 to 14, in which the achiral component T further contains at
least one compound selected from the group consisting of compounds
of Formulas (7), (8), (9), (10), and (11).
##STR00013##
[0058] (in the formulas, R.sup.5 and R.sup.6 are each independently
a C.sub.1-10 alkyl or a C.sub.2-10 alkenyl, wherein arbitrary
hydrogen in the alkyl and the alkenyl may be substituted with
fluorine, and arbitrary --CH.sub.2-- in the alkyl, the alkenyl, or
the alkyl and the alkenyl with arbitrary hydrogen substituted with
fluorine may be substituted with --O--; Rings D.sup.1, D.sup.2,
D.sup.3, and D.sup.4 are each independently 1,4-cyclohexylene,
1,4-cyclohexenylene, 1,4-phenylene, 1,4-phenylene with arbitrary
hydrogen substituted with fluorine, tetrahydropyran-2,5-diyl, or
decahydronaphthalene-2,6-diyl; Z.sup.13, Z.sup.14, Z.sup.15, and
Z.sup.16 are each independently --(CH.sub.2).sub.2--, --COO--,
--CH.sub.2O--, --OCF.sub.2--, --OCF.sub.2 (CH.sub.2).sub.2--, or a
single bond; L.sup.13 and L.sup.14 are each independently fluorine
or chlorine; and t, u, x, y, and z are each independently 0 or 1,
and u+x+y+z is 1 or 2.)
[0059] [18] The liquid crystal composition according to any one of
items 1 to 14, in which the achiral component T further contains at
least one compound selected from the group consisting of the
compounds of Formulas (12), (13), and (14).
##STR00014##
[0060] (in the formulas, R.sup.7 and R.sup.8 are each independently
a C.sub.1-10 alkyl or a C.sub.2-10 alkenyl, in which arbitrary
hydrogen in the alkyl and the alkenyl may be substituted with
fluorine, and arbitrary --CH.sub.2-- in the alkyl, the alkenyl, or
the alkyl and the alkenyl with arbitrary hydrogen substituted with
fluorine may be substituted with --O--; Rings E.sup.1, E.sup.2, and
E.sup.3 are each independently 1,4-cyclohexylene,
pyrimidine-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene,
3-fluoro-1,4-phenylene, or 2,5-difluoro-1,4-phenylene; Z.sup.17 and
Z.sup.18 are each independently --C.ident.C--, --COO--,
--(CH.sub.2).sub.2--, --CH.dbd.CH--, or a single bond.)
[0061] [19] The liquid crystal composition according to item 15,
further containing at least one compound selected from the group
consisting of the compound of Formula (6) according to item 16.
[0062] [20] The liquid crystal composition according to item 15,
further containing at least one compound selected from the group
consisting of the compounds of Formula (12), (13), and (14)
according to item 18.
[0063] [21] The liquid crystal composition according to item 16,
further containing at least one compound selected from the group
consisting of the compounds of Formulas (12), (13), and (14)
according to item 18.
[0064] [22] The liquid crystal composition according to item 17,
further containing at least one compound selected from the group
consisting of the compounds of Formulas (12), (13), and (14)
according to item 18.
[0065] [23] The liquid crystal composition according to any one of
items 1 to 14, in which the achiral component T further contains at
least one compound selected from the group consisting of the
compounds of Formulas (15), (16), (17), and (18).
##STR00015##
[0066] (in the formulas, R.sup.9 is a C.sub.1-10 alkyl, a
C.sub.2-10 alkenyl, or a C.sub.2-10 alkynyl, in which arbitrary
hydrogen in the alkyl, the alkenyl and the alkynyl may be
substituted with fluorine, and arbitrary --CH.sub.2-- in the alkyl,
the alkenyl, the alkynyl, or the alkyl, the alkenyl and the alkynyl
with arbitrary hydrogen substituted with fluorine may be
substituted with --O--; X.sup.5 is fluorine, chlorine, --SF.sub.5,
--OCF.sub.3, --OCHF.sub.2, --CF.sub.3, --CHF.sub.2, --CH.sub.2CH,
--OCF.sub.2CHF.sub.2, or --OCF.sub.2CHFCF.sub.3; Rings F.sup.1,
F.sup.2, F.sup.3, and F.sup.4 are each independently
1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl,
tetrahydropyran-2,5-diyl, 1,4-phenylene, naphthalene-2,6-diyl,
1,4-phenylene with arbitrary hydrogen substituted with fluorine or
chlorine, or naphthalene-2,6-diyl with arbitrary hydrogen
substituted with fluorine or chlorine; in Formulas (17), Ring
F.sup.1 is 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl,
pyrimidine-2,5-diyl, tetrahydropyran-2,5-diyl, 1,4-phenylene,
naphthalene-2,6-diyl, or naphthalene-2,6-diyl with arbitrary
hydrogen substituted with fluorine or chlorine; Z.sup.19, Z.sup.20,
and Z.sup.21 are each independently --(CH.sub.2).sub.2--,
--(CH.sub.2).sub.4--, --COO--, --CF.sub.2O--, --OCF.sub.2--,
--CH.dbd.CH--, --C.ident.C--, --CH.sub.2O--, or a single bond; and
L.sup.15 and L.sup.16 are each independently hydrogen or
fluorine.)
[0067] [24] The liquid crystal composition according to any one of
items 1 to 14, in which the achiral component T further contains at
least one compound selected from the group consisting of the
compound of Formula (19).
##STR00016##
[0068] (in the formulas, R.sup.10 is a C.sub.1-10 alkyl, a
C.sub.2-10 alkenyl, or a C.sub.2-10 alkynyl, in which arbitrary
hydrogen in the alkyl, the alkenyl and the alkynyl may be
substituted with fluorine, and arbitrary --CH.sub.2-- in the alkyl,
the alkenyl, the alkynyl, or the alkyl, the alkenyl and the alkynyl
with arbitrary hydrogen substituted with fluorine may be
substituted with --O--; X.sup.6 is --C.ident.N, --N.dbd.C.dbd.S, or
--C.ident.C--C.ident.N; Rings G.sup.1, G.sup.2, and G.sup.3 are
each independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene
with arbitrary hydrogen substituted with fluorine or chlorine,
naphthalene-2,6-diyl, naphthalene-2,6-diyl with arbitrary hydrogen
substituted with fluorine or chlorine, 1,3-dioxane-2,5-diyl,
tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; Z.sup.22 is
--(CH.sub.2).sub.2--, --COO--, --CF.sub.2O--, --OCF.sub.2--,
--C.ident.C--, --CH.sub.2O--, or a single bond; L.sup.17 and
L.sup.18 are each independently hydrogen or fluorine; and aa is 0,
1 or 2, ab is 0 or 1, and aa+ab is 0, 1 or 2.)
[0069] [25] The liquid crystal composition according to any one of
items 1 to 24, containing at least one antioxidant and/or UV
absorbent.
[0070] [26] The liquid crystal composition according to any one of
items 1 to 25, in which the optically isotropic liquid crystal
phase does not exhibit two or more colors of diffracted light.
[0071] [27] The liquid crystal composition according to any one of
items 1 to 25, in which the optically isotropic liquid crystal
phase exhibits two or more colors of diffracted light.
[0072] [28] The liquid crystal composition according to item 26 or
27, obtained by adding the chiral reagent into a composition having
a temperature difference of 3.degree. C.-150.degree. C. between an
upper-limit temperature and a lower-limit temperature of
co-existence of a chiral nematic phase and a non-liquid crystal
isotropic phase.
[0073] [29] The liquid crystal composition according to item 26 or
27, obtained by adding the chiral reagent into a composition having
a temperature difference of 5.degree. C.-150.degree. C. between an
upper-limit temperature and a lower-limit temperature of
co-existence of a chiral nematic phase and a non-liquid crystal
isotropic phase.
[0074] [30] The liquid crystal composition according to item 26 or
27, obtained by adding the chiral reagent into a composition having
a temperature difference of 3.degree. C.-150.degree. C. between an
upper-limit temperature and a lower-limit temperature of
co-existence of a nematic phase and a non-liquid crystal isotropic
phase.
[0075] [31] The liquid crystal composition according to any one of
items 1 to 30, in which a content of the chiral reagent is 1-40 wt
% based on the total weight of the liquid crystal composition.
[0076] [32] The liquid crystal composition according to any one of
items 1 to 30, in which a content of the chiral reagent is 5-15 wt
% based on the total weight of the liquid crystal composition.
[0077] [33] The liquid crystal composition according to item 31 or
32, exhibiting a chiral nematic phase at any temperature in the
range of 70.degree. C. to -20.degree. C., and having a helical
pitch of 700 nm or less within at least a part of the temperature
range.
[0078] [34] The liquid crystal composition according to any one of
items 31 to 33, in which the chiral reagent contains at least one
compound selected from the group consisting of the compounds of
Formulas (K1)-(K5).
##STR00017##
[0079] (in Formulas (K1)-(K5), R.sup.K is each independently
hydrogen, halogen, --C.ident.N, --N.dbd.C.dbd.O, --N.dbd.C.dbd.S,
or a C.sub.1-20 alkyl, wherein arbitrary --CH.sub.2-- in the alkyl
may be substituted with --O--, --S--, --COO--, --OCO--,
--CH.dbd.CH--, --CF.dbd.CF-- or --C.ident.C--, arbitrary hydrogen
in the alkyl may be substituted with halogen, and additionally, a
terminal --CH.sub.3 may be substituted with:
##STR00018##
[0080] A is each independently an aromatic or non-aromatic 3- to
8-membered ring, or a fused ring having 9 or more carbon atoms,
wherein arbitrary hydrogen in the rings may be substituted with
halogen, a C.sub.1-3 alkyl or haloalkyl, --CH.sub.2-- in the rings
may be substituted with --O--, --S--, or --NH--, and --CH.dbd. in
the rings may be substituted with --N.dbd.; B is each independently
hydrogen, halogen, a C.sub.1-3 alkyl, a C.sub.1-3 haloalkyl, an
aromatic or non-aromatic 3- to 8-membered ring, or a fused ring
having 9 or more carbon atoms, wherein arbitrary hydrogen in the
rings may be substituted with halogen, a C.sub.1-3 alkyl or
haloalkyl, --CH.sub.2-- in the rings may be substituted with --O--,
--S-- or --NH--, and --CH.dbd. in the rings may be substituted with
--N.dbd.; Z is each independently a single bond, or a C.sub.1-8
alkylene, wherein arbitrary --CH.sub.2-- in the alkylene may be
substituted with --O--, --S--, --COO--, --OCO--, --CSO--, --OCS--,
--N.dbd.N--, --CH.dbd.N--, --N.dbd.CH--, --CH.dbd.CH--,
--CF.dbd.CF--, or --C.ident.C--, and arbitrary hydrogen in the
alkylene may be substituted with halogen;
[0081] X is a single bond, --COO--, --OCO--, --CH.sub.2O--,
--OCH.sub.2--, --CF.sub.2O--, --OCF.sub.2--, or
--CH.sub.2CH.sub.2--; and
[0082] mK is an integer of 1-4.)
[0083] [35] The liquid crystal composition according to items 31 to
33, in which the chiral reagent contains at least one compound
selected from the group consisting of the compounds of Formulas
(K2-1)-(K2-8), Formulas (K4-1)-(K4-6), and Formulas
(K5-1)-(K5-3).
##STR00019## ##STR00020##
[0084] (in the formulas, R.sup.K is each independently a C.sub.3-10
alkyl, wherein --CH.sub.2-- adjacent to the ring in the alkyl may
be substituted with --O--, and arbitrary --CH.sub.2-- in the alkyl
may be substituted with --CH.dbd.CH--.)
[0085] [36] A mixture, containing the liquid crystal composition
according to any one of items 1 to 35 and a polymerizable
monomer.
[0086] [37] The mixture according to item 36, in which the
polymerizable monomer is a photopolymerizable monomer or a
thermal-polymerizable monomer.
[0087] [38] A polymer/liquid crystal composite material, obtained
by polymerizing the mixture according to item 36 or 37, for use in
a device driven in an optically isotropic liquid crystal phase.
[0088] [39] The polymer/liquid crystal composite material according
to item 38, obtained by polymerizing the mixture according to item
36 or 37 in a non-liquid crystal isotropic phase or an optically
isotropic liquid crystal phase.
[0089] [40] The polymer/liquid crystal composite material according
to item 38 or 39, in which the polymer contained in the
polymer/liquid crystal composite material has a mesogen moiety.
[0090] [41] The polymer/liquid crystal composite material according
to any one of items 38 to 40, in which the polymer contained in the
polymer/liquid crystal composite material has a cross-linked
structure.
[0091] [42] The polymer/liquid crystal composite material according
to any one of items 38 to 41, in which a content of the liquid
crystal composition is 60-99 wt %, and a content of the polymer is
1-40 wt %.
[0092] [43] An optical device, provided with a liquid crystal
medium disposed between substrates having electrodes disposed on
either or both surfaces thereof and an electric field-applying
means for applying an electric field to the liquid crystal medium
via the electrodes, in which the liquid crystal medium is the
liquid crystal composition according to any one of items 31 to 35
or the polymer/liquid crystal composite material according to any
one of items 38 to 42.
[0093] [44] An optical device, provided with a set of substrates
having electrodes disposed on either or both surfaces thereof, at
least one of which being transparent, a liquid crystal medium
disposed between the substrates, a polarizer disposed outside of
the substrates, and an electric field-applying means for applying
an electric field to the liquid crystal medium via the electrodes,
in which the liquid crystal medium is the liquid crystal
composition or the polymer/liquid crystal composite material
according to any one of items 31 to 35 or the polymer/liquid
crystal composite material according to any one of items 38 to
42.
[0094] [45] The optical device according to item 43 or 44, in which
on at least one of the set of substrates, the electrodes are
configured in a manner such that an electric field is applied in at
least two directions.
[0095] [46] The optical device according to item 43 or 44, in which
on one or two of the set of substrates disposed in parallel with
each other, the electrodes are configured in a manner such that an
electric field is applied in at least two directions.
[0096] [47] The optical device according to any one of items 43 to
46, in which the electrodes are configured in a matrix to form
pixel electrodes, and each pixel is provided with an active element
being a thin film transistor (TFT).
[0097] In the present invention, the so-called liquid crystal
medium is a general term of a liquid crystal composition and a
polymer/liquid crystal composite. Furthermore, as described above,
the so-called optical device refers to various devices using
electro-optic effect to achieve the function of optical modulation
or optical switching, for example, display devices (LCD devices),
and optical modulation devices used in optical communication
systems, optical information processing or various sensor systems.
As for the optical modulation with changes in refractive index
caused by applying a voltage to an optically isotropic liquid
crystal medium, the Kerr effect is known. The so-called Kerr effect
is a phenomenon, in which the electric birefringence value
.DELTA.n(E) is proportional to the square of electric field E, that
is, .DELTA.n(E)=K.lamda.E.sup.2 (K=Kerr coefficient (or Kerr
constant), .lamda.: wavelength), for a material exhibiting the Kerr
effect. Herein, the so-called electric birefringence value refers
to a refractive index anisotropy value induced by applying an
electric field to an isotropic medium.
[0098] The terms used in the specification are defined as follows.
The liquid crystal compound is a general term of compounds having a
liquid crystal phase such as nematic phase and smectic phase and
compounds having no liquid crystal phase but being useful as a
component of a liquid crystal composition. The chiral reagent is an
optically active compound, which is added to impart the necessary
twisted molecular arrangement to a liquid crystal composition. The
LCD device is a general term of LCD panels and LCD modules. The
liquid crystal compound, the liquid crystal composition, and the
LCD device are sometimes simply referred as the compound, the
composition, and the device, respectively. Furthermore, for
example, the upper-limit temperature of a liquid crystal phase is
the phase transition temperature from the liquid crystal phase to
the isotropic phase, and simply referred as the clearing point or
upper-limit temperature. The lower-limit temperature of the liquid
crystal phase is simply referred as the lower-limit temperature.
The compound of Formula (1) is simply referred as Compound (1), and
the similar reference is also correspondingly applied to a compound
of Formula (2). In Formulas (1)-(19), the symbols B, D, and E
surrounded by hexagons are corresponding to rings B, D, and E,
respectively. The compound content by percentage is weight percent
(wt %) based on the total weight of the composition. Numerous
identical symbols such as rings A.sup.1, Y.sup.1, or B are included
in the same or different formulas; however, the groups represented
by these symbols can be identical or different.
[0099] "Arbitrary" denotes not only arbitrary position, but also
arbitrary number, except for the case when the number is 0. The
expression that arbitrary A may be substituted with B, C, or D not
only means arbitrary A may be substituted with B, arbitrary A may
be substituted with C, and arbitrary A may be substituted with D,
but also means that a plurality of A may be substituted with at
least two of B-D. For example, the alkyl in which arbitrary
--CH.sub.2-- may be substituted with --O-- or --CH.dbd.CH--
includes alkyl, alkenyl, alkoxy, alkoxyalkyl, alkoxyalkenyl,
alkenyloxyalkyl, and so on. Furthermore, in the present invention,
two contiguous --CH.sub.2-- being substituted with --O-- to form
--O--O-- is unsuitable, and the terminal --CH.sub.2-- in an alkyl
being substituted with --O-- is also unsuitable. The present
invention will be further described below. The terminal groups,
rings, and linking groups of the compound of Formula (1) will also
be illustrated with preferred examples.
EFFECTS OF THE INVENTION
[0100] The liquid crystal composition of the present invention is
stable to heat and light, and has an optically isotropic liquid
crystal phase having a high upper-limit temperature and a low
lower-limit temperature, and has a low driving voltage when being
used in a device driven in an optically isotropic liquid crystal
phase. The polymer/liquid crystal composite material of the present
invention includes a material of an optically isotropic liquid
crystal phase that exhibits a high upper-limit temperature and a
low lower-limit temperature, and has a low driving voltage when
being used in a device driven in an optically isotropic liquid
crystal phase.
[0101] The optical device of the present invention driven in an
optically isotropic liquid crystal phase has a wide usable
temperature range, a short response time, a high contrast, and a
low driving voltage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0102] FIG. 1 shows a comb-like electrode substrate used in an
embodiment.
[0103] FIG. 2 shows an optical system used in an embodiment.
DESCRIPTION OF THE EMBODIMENTS
[0104] 1-1 Compound (1)
[0105] The liquid crystal composition exhibiting an optically
isotropic liquid crystal phase of the present invention contains an
achiral component T and a chiral reagent, wherein the achiral
component T contains a compound of Formula (1) as Component A. A
first aspect of the present invention is that the achiral component
T contains only Component A, the achiral component T contains
Component A and Component B of Formula (2), the achiral component T
contains Component A and other components not specifically
disclosed in the specification, or the achiral component T contains
Component A, Component B, and other components not specifically
disclosed in the specification. In order for the liquid crystal
composition of the present invention to exhibit excellent
properties, it is preferred that 0.1-100 wt % of at least one of
the compound of Formula (1) of the present invention is contained
as the achiral component T.
[0106] The compound of Formula (1) is described.
##STR00021##
[0107] In Formulas (1), R.sup.1 is hydrogen or a C.sub.1-20 alkyl,
wherein arbitrary --CH.sub.2-- in the alkyl may be substituted with
--O--, --S--, --COO--, --OCO--, --CH.dbd.CH--, --CF.dbd.CF-- or
--C.ident.C--, and arbitrary hydrogen in the alkyl and the alkyl
with arbitrary --CH.sub.2-- substituted with --O--, --S--, --COO--,
--OCO--, --CH.dbd.CH--, --CF.dbd.CF-- or --C.ident.C-- may be
substituted with halogen or a C.sub.1-3 alkyl; Z.sup.1, Z.sup.2,
and Z.sup.3 are each independently a single bond, --COO--, or
--CF.sub.2O--, provide that at least one of Z.sup.1, Z.sup.2, and
Z.sup.3 is --CF.sub.2O--; L.sup.1, L.sup.2, L.sup.3, L.sup.4, and
L.sup.5 are each independently hydrogen or fluorine; X.sup.1 is
hydrogen, halogen, --SF.sub.5, or a C.sub.1-10 alkyl, wherein
arbitrary --CH.sub.2-- in the alkyl may be substituted with --O--,
--S--, --CH.dbd.CH--, or --C.ident.C--, and arbitrary hydrogen in
the alkyl or the alkyl with arbitrary --CH.sub.2-- substituted with
--O--, --S--, --CH.dbd.CH-- or --C.ident.C-- may be substituted
with fluorine.
[0108] As for such a R.sup.1, a linear group is preferred to a
branched group. A preferred stereo configuration of --CH.dbd.CH--
in alkenyl depends on the position of the double bond. A
trans-configuration is preferred for such an alkenyl having a
double bond at an odd position, such as --CH.dbd.CHCH.sub.3,
--CH.dbd.CHC.sub.2H.sub.5, --CH.dbd.CHC.sub.3H.sub.7,
--CH.dbd.CHC.sub.4H.sub.9, --C.sub.2H.sub.4CH.dbd.CHCH.sub.3, and
--C.sub.2H.sub.4CH.dbd.CHC.sub.2H.sub.5. A cis-configuration is
preferred for such an alkenyl having a double bond at an even
position, such as --CH.sub.2CH.dbd.CHCH.sub.3,
--CH.sub.2CH.dbd.CHC.sub.2H.sub.5, and
--CH.sub.2CH.dbd.CHC.sub.3H.sub.7. An alkenyl compound having a
preferred stereo configuration has a high upper-limit temperature
or has a liquid crystal phase over a wide temperature range, as
illustrated in detail in Mol. Cryst. Liq. Cryst., 1985, 131, 109
and Mol. Cryst. Liq. Cryst., 1985, 131, 327.
[0109] The alkyl may be linear or branched, and specific examples
include --CH.sub.3, --C.sub.2H.sub.5, --C.sub.3H.sub.7,
--C.sub.4H.sub.9, --C.sub.5H.sub.11, --C.sub.6H.sub.13,
--C.sub.7H.sub.15, --C.sub.8H.sub.17, --C.sub.9H.sub.19,
--C.sub.10H.sub.21, --C.sub.11H.sub.23, --C.sub.12H.sub.25,
--C.sub.13H.sub.27, --C.sub.14H.sub.29, and --C.sub.15H.sub.31.
[0110] The alkoxy may be linear or branched, and specific examples
include --OCH.sub.3, --OC.sub.2H.sub.5, --OC.sub.3H.sub.7,
--OC.sub.4H.sub.9, --OC.sub.5H.sub.11, --OC.sub.6H.sub.13,
--OC.sub.7H.sub.15, --OC.sub.8H.sub.17, --OC.sub.9H.sub.19,
--OC.sub.10H.sub.21, --OC.sub.11H.sub.23, --OC.sub.12H.sub.25,
--OC.sub.13H.sub.27, and --OC.sub.14H.sub.29.
[0111] The alkoxyalkyl may be linear or branched, and specific
examples include --CH.sub.2OCH.sub.3, --CH.sub.2OC.sub.2H.sub.5,
--CH.sub.2OC.sub.3H.sub.7, --(CH.sub.2).sub.2--OCH.sub.3,
--(CH.sub.2).sub.2--OC.sub.2H.sub.5,
--(CH.sub.2).sub.2--OC.sub.3H.sub.7, --(CH.sub.2).sub.3--OCH.sub.3,
--(CH.sub.2).sub.4--OCH.sub.3, and
--(CH.sub.2).sub.5--OCH.sub.3.
[0112] The alkenyl may be linear or branched, and specific examples
include --CH.dbd.CH.sub.2, --CH.dbd.CHCH.sub.3,
--CH.sub.2CH.dbd.CH.sub.2, --CH.dbd.CHC.sub.2H.sub.5,
--CH.sub.2CH.dbd.CHCH.sub.3, --(CH.sub.2).sub.2--CH.dbd.CH.sub.2,
--CH.dbd.CHC.sub.3H.sub.7, --CH.sub.2CH.dbd.CHC.sub.2H.sub.5,
--(CH.sub.2).sub.2--CH.dbd.CHCH.sub.3, and
--(CH.sub.2).sub.3--CH.dbd.CH.sub.2.
[0113] The alkenyloxy may be linear or branched, and specific
examples include --OCH.sub.2CH.dbd.CH.sub.2,
--OCH.sub.2CH.dbd.CHCH.sub.3, and
--OCH.sub.2CH.dbd.CHC.sub.2H.sub.5.
[0114] The alkynyl may be linear or branched, and specific examples
include --C.ident.CH, --C.ident.CCH.sub.3, --CH.sub.2C.ident.CH,
--C.ident.CC.sub.2H.sub.5, --CH.sub.2C.ident.CCH.sub.3,
--(CH.sub.2).sub.2--C.ident.CH, --C.ident.CC.sub.3H.sub.7,
--CH.sub.2C.ident.CC.sub.2H.sub.5,
--(CH.sub.2).sub.2--C.ident.CCH.sub.3, and
--C.ident.C(CH.sub.2).sub.5.
[0115] Preferably, R.sup.1 has a structure of Formulas
(CHN-1)-(CHN-19). Herein, R.sup.1a is hydrogen, or a C.sub.1-20
alkyl. More preferably, R.sup.1 has a structure of Formulas
(CHN-1)-(CHN-4) or Formulas (CHN-6)-(CHN-7).
##STR00022##
[0116] In Formula (1), Z.sup.1, Z.sup.2, and Z.sup.3 are each
independently a single bond, --COO--, or --CF.sub.2O--, provided
that at least one of Z.sup.1, Z.sup.2, and Z.sup.3 is
--CF.sub.2O--.
[0117] Preferred examples of Z.sup.1, Z.sup.2, and Z.sup.3 include
a single bond and --CF.sub.2O--.
[0118] In Formula (1), L.sup.1, L.sup.2, L.sup.3, L.sup.4, and
L.sup.5 are each independently hydrogen or fluorine. Furthermore,
preferably L.sup.2 and L.sup.4 are fluorine, and more preferably,
L.sup.2, L.sup.4 and L.sup.5 are fluorine.
[0119] In Formula (1), X.sup.1 is hydrogen, halogen, --SF.sub.5, or
a C.sub.1-10 alkyl, wherein arbitrary --CH.sub.2-- in the alkyl may
be substituted with --O--, --S--, --CH.dbd.CH-- or --C.ident.C--,
and arbitrary hydrogen in the alkyl and the alkyl with arbitrary
--CH.sub.2-- substituted with --O--, --S--, --CH.dbd.CH-- or
--C.ident.C-- may be substituted with fluorine.
[0120] Specific examples of the alkyl with arbitrary hydrogen
substituted with halogen include --CH.sub.2CH, --CHF.sub.2,
--CF.sub.3, --(CH.sub.2).sub.2--F, --CF.sub.2CH.sub.2CH,
--CF.sub.2CHF.sub.2, --CH.sub.2CF.sub.3, --CF.sub.2CF.sub.3,
--(CH.sub.2).sub.3--F, --(CF.sub.2).sub.3--F,
--CF.sub.2CHFCF.sub.3, --CHFCF.sub.2CF.sub.3,
--(CH.sub.2).sub.4--F, --(CF.sub.2).sub.4--F,
--(CH.sub.2).sub.5--F, and --(CF.sub.2).sub.5--F.
[0121] Specific examples of alkoxy with arbitrary hydrogen
substituted with halogen include --OCH.sub.2CH, --OCHF.sub.2,
--OCF.sub.3, --O--(CH.sub.2).sub.2--F, --OCF.sub.2CH.sub.2CH,
--OCF.sub.2CHF.sub.2, --OCH.sub.2CF.sub.3,
--O--(CH.sub.2).sub.3--F, --O--(CF.sub.2).sub.3--F,
--OCF.sub.2CHFCF.sub.3, --OCHFCF.sub.2CF.sub.3,
--O(CH.sub.2).sub.4--F, --O--(CF.sub.2).sub.4--F,
--O--(CH.sub.2).sub.5--F, and --O--(CF.sub.2).sub.5--F.
[0122] Specific examples of alkenyl with arbitrary hydrogen
substituted with halogen include --CH.dbd.CHF, --CH.dbd.CF.sub.2,
--CF.dbd.CHF, --CH.dbd.CHCH.sub.2CH, --CH.dbd.CHCF.sub.3,
--(CH.sub.2).sub.2--CH.dbd.CF.sub.2, --CH.sub.2CH.dbd.CHCF.sub.3,
--CH.dbd.CHCF.sub.3, and --CH.dbd.CHCF.sub.2CF.sub.3.
[0123] Specific examples of X.sup.1 include hydrogen, fluorine,
chlorine, --C.ident.N, --N.dbd.C.dbd.S, --SF.sub.5, --CH.sub.3,
--C.sub.2H.sub.5, --C.sub.3H.sub.7, --C.sub.4H.sub.9,
--C.sub.5H.sub.11, --C.sub.6H.sub.13, --C.sub.7H.sub.15,
--C.sub.8H.sub.17, --C.sub.9H.sub.19, --C.sub.10H.sub.21,
--CH.sub.2CH, --CHF.sub.2, --CF.sub.3, --(CH.sub.2).sub.2--F,
--CF.sub.2CH.sub.2CH, --CF.sub.2CHF.sub.2, --CH.sub.2CF.sub.3,
--CF.sub.2CF.sub.3, --(CH.sub.2).sub.3--F, --(CF.sub.2).sub.3--F,
--CF.sub.2CHFCF.sub.3, --CHFCF.sub.2CF.sub.3,
--(CH.sub.2).sub.4--F, --(CF.sub.2).sub.4--F,
--(CH.sub.2).sub.5--F, --(CF.sub.2).sub.5--F, --OCH.sub.3,
--OC.sub.2H.sub.5, --OC.sub.3H.sub.7, --OC.sub.4H.sub.9,
--OC.sub.5H.sub.11, --OCH.sub.2CH, --OCHF.sub.2, --OCF.sub.3,
--O--(CH.sub.2).sub.2--F, --OCF.sub.2CH.sub.2CH,
--OCF.sub.2CHF.sub.2, --OCH.sub.2CF.sub.3,
--O--(CH.sub.2).sub.3--F, --O--(CF.sub.2).sub.3--F,
--OCF.sub.2CHFCF.sub.3, --OCHFCF.sub.2CF.sub.3,
--O(CH.sub.2).sub.4--F, --O--(CF.sub.2).sub.4--F,
--O--(CH.sub.2).sub.5--F, --O--(CF.sub.2).sub.5--F,
--CH.dbd.CH.sub.2, --CH.dbd.CHCH.sub.3, --CH.sub.2CH.dbd.CH.sub.2,
--CH.dbd.CHC.sub.2H.sub.5, --CH.sub.2CH.dbd.CHCH.sub.3,
--(CH.sub.2).sub.2--CH.dbd.CH.sub.2, --CH.dbd.CHC.sub.3H.sub.7,
--CH.sub.2CH.dbd.CHC.sub.2H.sub.5,
--(CH.sub.2).sub.2--CH.dbd.CHCH.sub.3,
--(CH.sub.2).sub.3--CH.dbd.CH.sub.2, --CH.dbd.CHF,
--CH.dbd.CF.sub.2, --CF.dbd.CHF, --CH.dbd.CHCH.sub.2CH,
--CH.dbd.CHCF.sub.3, --(CH.sub.2).sub.2--CH.dbd.CF.sub.2,
--CH.dbd.CHCF.sub.3, --CH.sub.2CH.dbd.CHCF.sub.3, and
--CH.dbd.CHCF.sub.2CF.sub.3.
[0124] Preferred examples of X.sup.1 include fluorine, chlorine,
--CF.sub.3, --CHF.sub.2, --OCF.sub.3, and --OCHF.sub.2. Most
preferred examples of X.sup.1 include fluorine, chlorine,
--CF.sub.3, and --OCF.sub.3.
[0125] In Formula (1), structures of Formulas (1-1)-(1-3) are
preferred.
##STR00023##
[0126] In the formulas, R.sup.1 has a structure of any one of
Formulas (CHN-1)-(CHN-19), R.sup.1a is hydrogen, or a C.sub.1-20
alkyl; L.sup.1, L.sup.2, L.sup.3, L.sup.4, and L.sup.5 are each
independently hydrogen or fluorine; and X.sup.1 is fluorine,
chlorine, --CF.sub.3, --CHF.sub.2, --OCF.sub.3, --OCHF.sub.2,
--C.ident.C--CF.sub.3, --CH.dbd.CHCF.sub.3, or
--OCF.sub.2CFHCF.sub.3.
[0127] 1-2 Properties of Compound (1)
[0128] Compound (1) used in the present invention is further
described in detail. Compound (1) is a compound having four benzene
rings and at least one linking group --CF.sub.2O--, which has very
stable physical and chemical properties under the conditions where
the device is conventionally used, and has an excellent
compatibility with other liquid crystal compounds. The composition
containing such a compound is stable under the conditions where the
device is conventionally used. Therefore, the composition
containing the compound has an expanded temperature range of an
optically isotropic liquid crystal phase, and thus can be used in a
display device over a wide temperature range. Moreover, due to
large dielectric anisotropy and large refractive index anisotropy,
the compound may be used as a component for lowering the driving
voltage of a composition driven in an optically isotropic liquid
crystal phase.
[0129] By properly selecting the left terminal group R.sup.1, the
groups on the benzene rings (L.sup.1-L.sup.5, and X.sup.1), or the
linking groups Z.sup.1-Z.sup.3 in Compound (1), the physical
properties such as clearing point, refractive index anisotropy, and
dielectric anisotropy can be adjusted at will. The effects of the
types of the left terminal group R.sup.1, the groups on the benzene
rings (L.sup.1-L.sup.5, and X.sup.1), or the linking groups
Z.sup.1-Z.sup.3 on the physical properties of Compound (1) will be
described below.
[0130] When R.sup.1 is linear, Compound (1) has a liquid crystal
phase over a wide temperature range and a low viscosity. When
R.sup.1 is branched, Compound (1) has good compatibility with other
liquid crystal compounds. When R.sup.1 is an alkenyl, a preferred
stereo configuration depends on the position of the double bond. An
alkenyl compound having a preferred stereo configuration has a high
upper-limit temperature or has a liquid crystal phase with over a
wide temperature range.
[0131] When the linking groups Z.sup.1, Z.sup.2, and Z.sup.3 are a
single bond or --CF.sub.2O--, Compound (1) has a low viscosity.
When the linking groups are Z.sup.1, Z.sup.2, and Z.sup.3 are
--COO--, or --CF.sub.2O--, Compound (1) has a large dielectric
anisotropy. When the linking groups Z.sup.1, Z.sup.2, and Z.sup.3
are a single bond, or --CF.sub.2O--, Compound (1) has stable
chemical properties, and is unlikely to be deteriorated.
[0132] When the right terminal group X.sup.1 is fluorine, chlorine,
--SF.sub.5, --CF.sub.3, --CHF.sub.2, --CH.sub.2CH, --OCF.sub.3,
--OCHF.sub.2, or --OCH.sub.2CH, Compound (1) has a large dielectric
anisotropy. When X.sup.1 is fluorine, --OCF.sub.3, or --CF.sub.3,
Compound (1) has stable chemical properties.
[0133] When the number of L.sup.1-L.sup.5, which is fluorine, is
large, Compound (1) has a large dielectric anisotropy. When L.sup.1
is hydrogen, Compound (1) has excellent compatibility with other
liquid crystal compounds. When L.sup.4 and L.sup.5 are both
fluorine, Compound (1) has an especially large dielectric
anisotropy.
[0134] As described above, a compound with target properties can be
obtained by properly selecting the types of the terminal groups,
linking groups, and the like.
[0135] 1-3 Specific Examples of Compound (1)
[0136] Preferred examples of Compound (1) include Formulas
(1-1)-(1-3). More preferred examples include Formulas
(1-2A)-(1-2H), and Formulas (1-3A)-(1-3C). Further more preferred
examples include Formulas (1-2A)-(1-2D), (1-3A), and (1-3B). Most
preferred examples include Formulas (1-2A) and (1-2C).
##STR00024## ##STR00025##
[0137] (in the formulas, R.sup.1 is a chain selected from Formulas
(CHN-1), (CHN-4), (CHN-7), (CHN-8), and (CHN-11); X.sup.1 is
fluorine, chlorine, --CF.sub.3, --CHF.sub.2, --CH.sub.2CH,
--OCF.sub.3, --OCHF.sub.2, --OCF.sub.2CFHCF.sub.3, or
--CH.dbd.CHCF.sub.3.)
[0138] 1-4Synthesis of Compound (1)
[0139] Next, the synthesis of Compound (1) is described. Compound
(1) may be synthesized by a suitable combination of organic
synthesis methods. The methods for introducing target terminal
groups, rings, and linking groups into a starting compound are
described in, for example, Organic Syntheses John Wiley & Sons,
Inc, Organic Reactions, John Wiley & Sons, Inc, Comprehensive
Organic Synthesis, Pergamon Press, and New Lectures on Experimental
Chemistry (Maruzen).
[0140] 1-4-2 Methods for Generating Linking Groups
Z.sup.1-Z.sup.3
[0141] An example of the methods for generating the linking groups
Z.sup.1-Z.sup.3 in Compound (1) is as shown in a scheme below. In
the scheme, MSG.sup.1 or MSG.sup.2 is monovalent organic group
having at least one ring. The multiple MSGs.sup.1 (or MSGs.sup.2)
in the scheme may be identical or different. Compounds (1A)-(1J)
are equivalent to Compound (1).
##STR00026##
[0142] Subsequently, as for the linking groups Z.sup.1-Z.sup.3 in
Compound (1), generation methods of various bonds are described in
Sections (I)-(III) below.
[0143] (I) Generation of a Single Bond
[0144] Arylboronic acid (20) is reacted with Compound (21)
synthesized via a well-known process in an aqueous carbonate
solution in presence of a catalyst such as
tetrakis(triphenylphosphine)palladium, to synthesize Compound (1A).
Compound (1A) may also be synthesized by reacting Compound (22)
synthesized via a well-known process with n-butyl lithium, then
with zinc chloride, and finally with Compound (21) in the presence
of a catalyst such as bis(triphenylphosphine)palladium
dichloride.
[0145] (II) Generation of --COO-- and --OCO--
[0146] Compound (22) is reacted with n-butyl lithium, and then with
carbon dioxide, to obtain a carboxylic acid (23). Compound (23) and
phenol (24) synthesized via a well-known process are dehydrated in
the presence of 1,3-dicyclohexylcarbodiimide (DCC) and
4-dimethylaminopyridine (DMAP), to synthesize Compound (1B) having
--COO--. A compound having --OCO-- may also be synthesized through
this method.
[0147] (III) Generation of --CF.sub.2O-- and --OCF.sub.2--
[0148] Compound (1B) is treated with a thionating agent such as
Lawesson's Reagent, to obtain Compound (25). Compound (25) is
florinated by using hydrogen fluoride pyridine complex and
N-bromosuccinimide (NBS), to synthesize Compound (1C) having
--CF.sub.2O--. See M. Kuroboshi et al., Chem. Lett., 1992, 827.
Compound (1C) may also be synthesized by fluorinating Compound (25)
with (diethylamino)sulfurtrifluoride (DAST). See W. H. Bunnelle et
al., J. Org. Chem. 1990, 55, 768. A compound having --OCF.sub.2--
may also be synthesized through this method. The linking groups may
also be generated by the method described in Peer. Kirsch et al.,
Angew. Chem. Int. Ed. 2001, 40, 1480.
[0149] 1-4-4 Methods for Synthesizing Compound (1)
[0150] There are many methods for synthesizing the compounds of
Formula (1), and they may be synthesized from commercially
available reagents, with proper reference to examples in the
specification, or documents and books.
[0151] 1-4-5 Methods for Synthesizing Compound (2)
[0152] There are many methods for synthesizing the compounds of
Formula (2), and they may be synthesized from commercially
available reagents, with proper reference to examples in the
specification, or documents and books.
[0153] 2 Compounds (2)-(18)
[0154] A second aspect of the present invention is a liquid crystal
composition containing an achiral component T and a chiral reagent,
wherein the achiral component T is obtained by adding a component
selected from Components B, C, D, and E below into Component A
formed of the compound of Formula (1). Compared with a composition
with an achiral component T containing Component A alone, the
liquid crystal composition may be freely adjusted for the driving
voltage, the temperature range of a liquid crystal phase, the
refractive index anisotropy value, the dielectric anisotropy value,
and viscosity.
[0155] The component added into the Component A is preferably
obtained by mixing Components B, C, D, or E, where Component B
contains at least one compound selected from the group consisting
of the compounds of Formula (2), Component C contains at least one
compound selected from the group consisting of the compounds of
Formulas (3), (4), and (5), Component D contains at least one
compound selected from the group consisting of the compounds of
Formula (6), and Component E contains at least one compound
selected from the group consisting of the compounds of Formulas
(7), (8), (9), (10), and (11).
[0156] Moreover, by mixing Component F containing at least one
compound selected from the group consisting of the compounds of
Formulas (12), (13), and (14), the threshold voltage, the
temperature range of a liquid crystal phase, the refractive index
anisotropy value, the dielectric anisotropy value, and the
viscosity may be adjusted.
[0157] The component added into the Component A is preferably
Component G containing at least one compound selected from the
group consisting of the compounds of Formulas (15), (16), and (17),
or Component H containing at least one compound selected from the
group consisting of the compounds of Formula (18). Components G and
H are especially useful for improving the refractive index
anisotropy value and the dielectric anisotropy value.
[0158] Moreover, for each component of the liquid crystal
composition used in the present invention, an analogue containing
isotopes of each element may be used, because no significant
difference in physical properties exists.
[0159] In Component B above, preferred examples of the compound of
Formula (2) include Formulas (2-1)-(2-9).
##STR00027##
[0160] (in the formulas, R.sup.2 and X.sup.2 have the same meaning
as R.sup.2 and X.sup.2 in Formula (2).)
[0161] In Component C, preferred examples of the compound of
Formula (3) include Formulas (3-1)-(3-16), preferred examples of
the compound of Formula (4) include Formulas (4-1)-(4-112), and
preferred examples of the compound of Formula (5) include Formulas
(5-1)-(5-52).
##STR00028## ##STR00029## ##STR00030## ##STR00031## ##STR00032##
##STR00033## ##STR00034## ##STR00035## ##STR00036## ##STR00037##
##STR00038## ##STR00039## ##STR00040## ##STR00041## ##STR00042##
##STR00043## ##STR00044## ##STR00045## ##STR00046## ##STR00047##
##STR00048## ##STR00049## ##STR00050##
[0162] (in the formulas, R.sup.3, and X.sup.3 having the same
meanings as those of R.sup.3, and X.sup.3 in Formulas (3)-(5).)
[0163] The compounds of Formulas (3)-(5) (i.e. Component C) have a
positive dielectric anisotropy value and excellent thermal or
chemical stability, and thus are useful for preparing a liquid
crystal composition for TFTs. Based on the total weight of the
liquid crystal composition of the present invention, the content of
Component C in the liquid crystal composition of the present
invention is suitably in a range of 1-99 wt %, preferably 1-60 wt
%, and more preferably 1-35 wt %. Furthermore, by further
containing the compounds of Formulas (12)-(14) (i.e., Component F),
the viscosity may be adjusted.
[0164] Preferred examples of the compound of Formula (6) (i.e.
Component D) include Formulas (6-1)-(6-62).
##STR00051## ##STR00052## ##STR00053## ##STR00054## ##STR00055##
##STR00056## ##STR00057## ##STR00058##
[0165] (in the formulas, R.sup.4 and X.sup.4 have the same meanings
as those of R.sup.4 and X.sup.4 in Formula (6).)
[0166] The compounds of Formula (6) (i.e., Component D) have a
positive and very large dielectric anisotropy value. By containing
Component D, the driving voltage of the composition is lowered. In
addition, the viscosity and refractive index anisotropy value can
be adjusted, and the temperature range of a liquid crystal phase
can be expanded.
[0167] Based on the total weight of the composition, the content of
Component D is preferably 0.1-99.9 wt %, more preferably 1-97 wt %,
and still more preferably 1-30 wt %. Furthermore, by mixing the
components below, the threshold voltage, the temperature range of a
liquid crystal phase, the refractive index anisotropy value,
dielectric anisotropy value, and the viscosity may be adjusted.
[0168] Component E containing at least one compound selected from
the group consisting of the compounds of Formulas (7)-(11) is a
preferred component for preparing the liquid crystal composition of
the present invention having a negative dielectric anisotropy
value.
[0169] Preferred examples of the compounds of Formulas (7)-(11)
(Component E) are respectively Formulas (7-1)-(7-5), Formulas
(8-1)-(8-9), Formulas (9-1)-(9-3), and Formulas (11-1)-(11-11).
##STR00059## ##STR00060## ##STR00061##
[0170] (in the formulas, R.sup.5 and R.sup.6 have the meanings as
those of R.sup.5 and R.sup.6 in Formulas (7)-(11).)
[0171] The compounds of the Component E are mainly used in the
liquid crystal
[0172] compositions having a negative dielectric anisotropy value.
In Component E, the compound of Formula (7) is a bicyclic compound,
thereby mainly having the effect of adjusting the threshold
voltage, the viscosity, or the refractive index anisotropy value.
Furthermore, the compounds of Formulas (8) and (9) are tricyclic
compounds, thereby having the effect of increasing the clearing
point, expanding the temperature range of an optically isotropic
liquid crystal phase, and increasing the refractive index
anisotropy value. The compounds of Formulas (10) and (11) have a
negative and large dielectric anisotropy value, thereby mainly
having the effect of adjusting the driving voltage.
[0173] In preparing a composition having a negative dielectric
anisotropy value, the content of Component E is preferably higher
than or equal to 40 wt %, and more preferably in the range of 50 wt
%-95 wt %, based on the total weight of the composition.
Furthermore, by mixing Component E, the elastic constant and the
voltage-transmittance curve of the composition may be controlled.
When mixing Component E into a composition having a positive
dielectric anisotropy value, the content of Component E is
preferably lower than or equal to 30 wt %, based on the total
weight of the composition.
[0174] Preferred examples of the compounds of Formulas (12), (13),
and (14) (Component F) include respectively Formulas
(12-1)-(12-11), Formulas (13-1)-(13-18), and Formulas
(14-1)-(14-6).
##STR00062## ##STR00063## ##STR00064##
[0175] (in the formulas, R.sup.7 and R.sup.8 have the same meaning
as R.sup.7 and R.sup.8 in Formulas (12)-(14).)
[0176] The compounds of Formulas (12)-(14) (Component F) are
compounds having a low absolute value of dielectric anisotropy, and
are nearly neutral. The compounds of Formula (12) mainly have the
effect of adjusting the viscosity or the refractive index
anisotropy value. Furthermore, the compounds of Formulas (13) and
(14) have the effect of increasing the clearing point and expanding
the temperature range of an optically isotropic liquid crystal
phase, or the effect of adjusting the refractive index anisotropy
value.
[0177] If the content of the compounds of Component F is increased,
the driving voltage of the liquid crystal composition is raised,
and the viscosity is lowered. Therefore, the content of the
compounds of Component E is expected to be as high as possible,
provided that the desired driving voltage of the liquid crystal
composition is met. In preparing a liquid crystal composition for a
TFT, the content of Component F is preferably 60 wt % or less, and
more preferably 40 wt % or less, based on the total weight of the
composition.
[0178] 3 Compound (15)-Compound (19)
[0179] A third aspect of the present invention is a liquid crystal
composition obtained by adding a component selected from Components
G and H below into Component A.
[0180] The component added into Component A is preferably obtained
by mixing Component G or H, where Component G contains at least one
compound selected from the group consisting of the compounds of
Formulas (15), (16), (17), and (18), and Component H contains at
least one compound selected from the group consisting of the
compounds of Formulas (19).
[0181] Moreover, for each component of the liquid crystal
composition of the present invention, an analogue containing
isotopes of each element also can be used, because no significant
difference in physical properties exists.
[0182] In Component G, preferred examples of the compounds of
Formula (15) include Formulas (15-1)-(15-8), preferred examples of
the compounds of Formula (16) include Formulas (16-1)-(16-26),
preferred examples of the compounds of Formula (17) include
Formulas (17-1)-(17-13), and preferred examples of the compounds of
Formula (18) include Formulas (18-1)-(18-12). Formulas (17-7), and
(17-8) have the effect of expanding the temperature range at a low
temperature side.
##STR00065## ##STR00066## ##STR00067## ##STR00068## ##STR00069##
##STR00070## ##STR00071##
[0183] (in the formulas, R.sup.9 and X.sup.5 have the same meaning
as R.sup.9 and X.sup.5 in Formulas (15)-(18), (F) denotes hydrogen
or fluorine, and (F, Cl) denotes hydrogen, fluorine or
chlorine.)
[0184] The compounds of Formulas (15)-(18) (i.e. Component G) have
a positive and very large dielectric anisotropy value and excellent
thermal or chemical stability, thereby being suitable for preparing
a liquid crystal composition used in active driving, such as TFT
driving. In the liquid crystal composition of the present
invention, the content of Component G is suitably in the range of 1
wt %-99 wt %, preferably 10 wt %-97 wt %, and more preferably 20 wt
%-95 wt %, based on the total weight of the liquid crystal
composition of the present invention. Furthermore, by further
containing the compounds of Formulas (12)-(14) (Component F), the
viscosity may be adjusted.
[0185] Preferred examples of the compounds of Formula (19) (i.e.
Component H) include Formulas (19-1)-(19-37).
##STR00072## ##STR00073## ##STR00074## ##STR00075##
##STR00076##
[0186] (in the formulas, R.sup.10 and X.sup.6 have the same meaning
as R.sup.10 and X.sup.6 in Formula (19), (F) denotes hydrogen or
fluorine, and (F, Cl) denotes hydrogen, fluorine, or chlorine.)
[0187] The compounds of Formula (19) (i.e., Component H) have a
positive and very large dielectric anisotropy value, thereby mainly
being used to lower the driving voltage of the devices. By
containing Component H, the driving voltage of the composition is
lowered, as well as the viscosity and the refractive index
anisotropy value may be adjusted, and the temperature range of a
liquid crystal phase is expanded. Moreover, the steepness is also
improved.
[0188] The content of Component H is preferably in the range of 0.1
wt %-99.9 wt %, more preferably 1 wt %-97 wt %, and more preferably
1 wt %-45 wt %, based on the total weight of the composition.
[0189] The liquid crystal composition of the present invention may
be prepared generally through a well-known method, for example, by
dissolving the required components at a high temperature.
[0190] 4 Composition Having Optically Isotropic Liquid Crystal
Phase
[0191] 4.1 Composition of Composition Having Optically Isotropic
Liquid Crystal Phase
[0192] A fourth aspect of the present invention is a composition
containing the compound of Formula (1) and a chiral reagent, which
is a liquid crystal composition useful in an optical device driven
in an optically isotropic liquid crystal phase and exhibiting an
optically isotropic liquid crystal phase.
[0193] Although being a tetracyclic compound, the compound of
Formula (1) has a low clearing point, and a large dielectric
anisotropy and a large refractive index anisotropy; therefore, in
order to exhibit excellent properties, the content of the compound
of Formula (1) is preferably 0.1-100 wt % based on the total weight
of the achiral component T without the chiral reagent. The content
of the compound of Formula (1) is more preferably 5-100 wt %, still
preferably 30-100 wt %, and still more preferably 70-100 wt %.
[0194] Furthermore, the compound of Formula (1-2) have good
compatibility with other liquid crystal compositions, and thus the
content thereof may be 5-100 wt %, preferably 20-100 wt %, and more
preferably 20-80 wt %, based on the total weight of the achiral
component T.
[0195] Based on the total weight of the liquid crystal composition
of the present invention, the content of the chiral reagent is
preferably 1-40 wt %, more preferably 3-25 wt %, and most
preferably 5-15 wt %. A liquid crystal composition containing the
chiral reagent in these ranges tends to have an optically isotropic
liquid crystal phase, and thus is preferred.
[0196] The chiral reagent contained in the liquid crystal
composition may be one, two, or more.
[0197] 4.2 Chiral Reagent
[0198] The chiral reagent contained in the optically isotropic
liquid crystal composition is not particularly limited, provided
that it is an optically active compound capable of twisting the
liquid crystal composition after being added into the achiral
component T. The chiral reagent is preferably a compound with a
large helical twisting power. As a compound with a large helical
twisting power reduces the adding amount required for obtaining a
desired pitch, a rise in the driving voltage can be suppressed,
which is advantageous in practice. Specifically, the compounds of
Formulas (K1)-(K5) below are preferred.
##STR00077##
[0199] (in Formulas (K1)-(K5), R.sup.K is each independently
hydrogen, halogen, --C.ident.N, --N.dbd.C.dbd.O, --N.dbd.C.dbd.S,
or a C.sub.1-20 alkyl, in which arbitrary --CH.sub.2-- may be
substituted with --O--, --S--, --COO--, --OCO--, --CH.dbd.CH--,
--CF.dbd.CF-- or --C.ident.C--, arbitrary hydrogen may be
substituted with halogen, and terminal --CH.sub.3 may be
substituted with
##STR00078##
[0200] A is each independently an aromatic or non-aromatic 3- to
8-membered ring, or a fused ring having 9 or more carbon atoms,
wherein arbitrary hydrogen in the rings may be substituted with
halogen or a C.sub.1-3 alkyl or haloalkyl, --CH.sub.2-- in the
rings may be substituted with --O--, --S-- or --NH--, and --CH.dbd.
in the rings may be substituted with --N.dbd.; B is each
independently hydrogen, halogen, a C.sub.1-3 alkyl, a C.sub.1-3
haloalkyl, an aromatic or non-aromatic 3- to 8-membered ring, or a
fused ring having 9 or more carbon atoms, wherein arbitrary
hydrogen in the rings may be substituted with halogen or a
C.sub.1-3 alkyl or haloalkyl, --CH.sub.2-- in the rings may be
substituted with --O--, --S-- or --NH--, and --CH.dbd. in the rings
may be substituted with --N.dbd.; and Z is each independently a
single bond, or a C.sub.1-8 alkylene, wherein arbitrary
--CH.sub.2-- in the alkylene may be substituted with --O--, --S--,
--COO--, --OCO--, --CSO--, --OCS--, --N.dbd.N--, --CH.dbd.N--,
--N.dbd.CH--, --CH.dbd.CH--, --CF.dbd.CF-- or --C.ident.C--, and
arbitrary hydrogen in the alkylene may be substituted with
halogen;
[0201] X is a single bond, --COO--, --OCO--, --CH.sub.2O--,
--OCH.sub.2--, --CF.sub.2O--, --OCF.sub.2-- or
--CH.sub.2CH.sub.2--;
[0202] mK is an integer of 1-4. Moreover, when two or more R.sup.K,
A, Z, and mK exist, the R.sup.K, A, Z, and mK may be identical or
different.)
[0203] Among the compounds, the chiral reagent added into the
liquid crystal composition is preferably Formulas (K2-1)-(K2-8)
included in Formula (K2), Formulas (K4-1)-(K4-6) included in
Formula (K4), and Formulas (K5-1)-(K5-3) included in Formula
(K5).
##STR00079## ##STR00080##
[0204] (in the formulas, R.sup.K is each independently a C.sub.3-10
alkyl, in which --CH.sub.2-adjacent to the ring in the alkyl may be
substituted with --O--, and arbitrary --CH.sub.2-- in the alkyl or
the alkyl with --CH.sub.2-- adjacent to the ring substituted with
--O-- may be substituted with --CH.dbd.CH--.)
[0205] 4.3 Optically Isotropic Liquid Crystal Phase
[0206] The so-called liquid crystal composition having optically
isotropy means that the composition exhibits an optical isotropy
because the liquid crystal molecules macroscopically have an
isotropic arrangement, but microscopically a liquid crystal order
exists. "Pitch corresponding to the microscopic liquid crystal
order of the liquid crystal composition (sometimes referred to as
pitch, hereafter)" is preferably 700 nm or less, more preferably
500 nm or less, and most preferably 350 nm or less.
[0207] Herein, the so-called "non-liquid crystal isotropic phase"
refers to a commonly defined isotropic phase (i.e. disordered
phase), and refers to an isotropic phase where a region with a
non-zero local order parameter is generated due to fluctuation. For
example, an isotropic phase exhibited at a high temperature side of
a nematic phase is equivalent to the non-liquid crystal isotropic
phase in the specification. The chiral liquid crystal in the
specification also has a similar definition. Moreover, the
so-called "optically isotropic liquid crystal phase" in the
specification means a phase that exhibits an optical isotropy
without fluctuation, an example of which is a phase exhibiting a
platelet tissue (i.e. blue phase in narrow sense).
[0208] The optically isotropic liquid crystal composition of the
present invention has an optically isotropic liquid crystal phase.
However, the typical platelet tissue is not observed in the blue
phase under a polarizing microscope sometimes. Therefore, in the
specification, a phase exhibiting the platelet tissue is designated
as blue phase, and an optically isotropic liquid crystal phase
including the blue phase is designated as optically isotropic
liquid crystal phase. That is, the blue phase is included in the
optically isotropic liquid crystal phase.
[0209] Generally, the blue phase is divided into three types, that
is, blue phase I, blue phase II, and blue phase III, and all the
three blue phases are optically active and isotropic. In the blue
phase I or blue phase II, two or more diffracted lights produced by
the Bragg reflection from different lattice planes are observed.
The blue phase is generally observed between the non-liquid crystal
isotropic phase and the chiral nematic phase.
[0210] The so-called state that the optically isotropic liquid
crystal phase does not exhibit two or more colors of diffracted
light means that a platelet tissue observed in the blue phase I and
blue phase II is not observed and the phase exhibits substantially
a single color in the entire plane. For an optically isotropic
liquid crystal phase not exhibiting two or more colors of
diffracted light, brightness/darkness of the colors is not
necessarily to be even in plane.
[0211] The optically isotropic liquid crystal phase not exhibiting
two or more colors of diffracted light has the advantage of
inhibiting the intensity of reflected light caused by Bragg
reflection, or shifting the reflected light toward the low
wavelength side.
[0212] Furthermore, when a liquid crystal material reflecting
visible light is used in a display device, a color variation
problem may sometimes occur. However, for a liquid crystal not
exhibiting two or more colors of diffracted light, because
reflection wavelength shift toward the low wavelength side, the
reflection of visible light may be eliminated by the pitch longer
than that in the blue phase in a narrow sense (a phase exhibiting
the platelet tissue).
[0213] The optically isotropic liquid crystal composition of the
present invention may be obtained by adding a chiral reagent into a
composition having a nematic phase. In this case, the chiral
reagent is preferably added in a concentration such that the pitch
is 700 nm or less. Furthermore, the composition having a nematic
phase contains the compound of Formula (1) and other optional
components. Moreover, the optically isotropic liquid crystal
composition of the present invention can also be obtained by adding
a chiral reagent to a composition having a chiral nematic phase but
no optically isotropic liquid crystal phase. Furthermore, the
composition having a chiral nematic phase but no optically
isotropic liquid phase contains the compound of Formula (1), an
optically active compound, and other optional components. In this
case, the optically active compound is preferably added in a
concentration such that the pitch is 700 nm or more, so as not to
exhibit an optically isotropic liquid crystal phase. Here, the
optically active compounds to be added may be the compounds with a
large helical twisting power above, that is, the compounds of
Formulas (K-1)-(K-5), Formulas (K2-1)-(K2-8), or Formulas
(K5-1)-(K5-3). Moreover, the optically active compound added may
not have a large helical twisting power. Such an optically active
compound is, for example, one added in a liquid crystal composition
for a device driven in a nematic phase (TN mode, STN mode, and the
like).
[0214] Examples of the optically active compound without a large
helical twisting power are the following optically active compounds
(Op-1)-(Op-13).
##STR00081## ##STR00082##
[0215] Moreover, the temperature range of the optically isotropic
liquid crystal composition of the present invention may be expanded
by adding a chiral reagent into a liquid crystal composition having
the co-existence of a nematic phase or a chiral nematic phase over
a wide temperature range and an isotropic phase for exhibiting an
optically isotropic liquid crystal phase. For example, a
composition exhibiting an optically isotropic liquid crystal phase
in a wide temperature range can be prepared as follows: a liquid
crystal compound having a high clearing point is mixed with a
liquid crystal compound having a low clearing point, and a liquid
crystal composition with a wide coexisting temperature range of a
nematic phase and an isotropic phase is prepared in a wide
temperature range; and then, a chiral reagent is added to the
liquid crystal composition.
[0216] For a liquid crystal composition with a wide coexisting
temperature range of a nematic phase or chiral nematic phase and an
isotropic phase, the difference between the upper-limit temperature
and lower-limit temperature of the co-existence of a chiral nematic
phase and a non-liquid crystal isotropic phase is preferably
3-150.degree. C., and more preferably 5-150.degree. C. Moreover,
the liquid crystal composition preferably has a difference of
3-150.degree. C. between the upper-limit temperature and
lower-limit temperature of the coexistence of a nematic phase and a
non-liquid crystal isotropic phase.
[0217] When an electric field is applied to the liquid crystal
medium of the present invention in an optically isotropic liquid
crystal phase, an electric birefringence occurs, but the Kerr
effect does not necessarily occur.
[0218] Because the electric birefringence effect of an optically
isotropic liquid crystal phase increases with the pitch, the
electric birefringence effect may be improved by adjusting the type
and content of the chiral reagent to increase the helical pitch,
provided that other optical properties, such as, transmittance and
diffraction wavelength, could be satisfied.
[0219] 4.4 Other Components
[0220] Other compounds, such as polymer material, may be further
added into the optically isotropic liquid crystal composition of
the present invention, so long as they do not affect the properties
of the composition. In addition to the polymer material, the liquid
crystal composition of the present invention can also contain, for
example, a dichroic dye or a photochromic compound. Examples of the
dichroic dye include merocyanine-based dyes, styryl-based dyes,
azo-based dyes, azomethine-based dyes, azoxy-based dyes,
quinophthalone-based dyes, anthraquinone-based dyes,
tetrazine-based dyes, and the like.
[0221] 5. Optically Isotropic Polymer/Liquid Crystal Composite
Material
[0222] A fifth aspect of the present invention is a composite
material of a polymer compound and a liquid crystal composition
containing the compound of Formula (1) and a chiral reagent, which
exhibits an optical isotropy. The composite material is an
optically isotropic polymer/liquid crystal composite material which
can be used in an optical device driven in an optically isotropic
liquid crystal phase. Such a polymer/liquid crystal composite
material is composed of, for example, the liquid crystal
composition according to Items [1]-[33] and a polymer.
[0223] The "polymer/liquid crystal composite material" of the
present invention has no particular limitation, provided that it is
a composite containing both a liquid crystal material and a polymer
compound. It also includes a state where the polymer compound and
the liquid crystal material are in phase separation because the
polymer compound is partially or entirely not dissolved in the
liquid crystal material. Furthermore, in the specification, a
nematic phase refers to one, in a narrow sense, excluding a chiral
nematic phase, unless specifically indicated.
[0224] The optically isotropic polymer/liquid crystal composite
material according to a preferred aspect of the present invention
can exhibit an optically isotropic liquid crystal phase in a wide
temperature range. Moreover, the polymer/liquid crystal composite
material according to a preferred aspect of the present invention
has very high response speed. Furthermore, based on such effects,
the polymer/liquid crystal composite material according to a
preferred aspect of the present invention is useful in an optical
device such as a display device.
[0225] 5.2 Polymers
[0226] Although the composite material of the present invention can
be produced by mixing an optically isotropic liquid crystal
composition with a pre-polymerized polymer, it is preferably
produced by mixing a low molecular weight monomer, macromonomer, or
oligomer, etc (generally referred to as "monomers", hereafter) to
be formed into a polymer material, with the liquid crystal
composition (cholesteric liquid crystal composition), and then
polymerizing the mixture. In the specification, the mixture
containing the monomers and the liquid crystal composition is
referred to as "polymerizable monomer/liquid crystal mixture". The
"polymerizable monomer/liquid crystal mixture" may optionally
contain a polymerization initiator, a curing agent, a catalyst, a
stabilizer, a dichroic dye, or a photochromic compound, and the
like, without compromising the effect of the present invention. For
example, the polymerizable monomer/liquid crystal mixture of the
present invention may also optionally contain 0.1-20 weight parts
of a polymerization initiator, based on 100 weight parts of the
polymerizable monomer.
[0227] The polymerization temperature is preferably such a
temperature that the polymer/liquid crystal composite material
exhibits high transparency and isotropy, and more preferably such a
temperature that the mixture of the monomer and the liquid crystal
material exhibits an isotropic phase or a blue phase, while the
polymerization is carried out in the isotropic phase or optically
isotropic liquid crystal phase. That is, the temperature is
preferably set, such that after the polymerization, the
polymer/liquid crystal composite material substantially does not
scatter light of wavelength greater than that of visible light and
exhibits an optical isotropy.
[0228] For example, a low molecular weight monomer, macromonomer,
and oligomer may be used as a raw material of the polymer compound
for forming the composite material of the present invention. In the
specification, the raw material monomers of the polymer compound
include low molecular weight monomers, macromonomers, oligomers,
and the like. Furthermore, the obtained polymer compound preferably
has a three-dimensional cross-linked structure, and thus the raw
material monomer of the polymer compound is preferably a
multi-functional monomer having two or more polymerizable
functional groups. The polymerizable functional groups have no
particular limitation, and include, for example, acryloyl,
methacryloyl, glycidyl, epoxy, oxetanyl, vinyl, and the like. In
view of the polymerization rate, acryloyl and methacryloyl are
preferred. The raw material monomers of the polymer compound
containing 10 wt % or more of the monomers having two or more
polymerizable functional groups are preferred, since the obtained
composite material of the present invention easily exhibits high
transparency and isotropy.
[0229] Moreover, in order to obtain a better composite material,
the polymer preferably has a mesogen moiety, and a part or all of
the raw material monomers used have a mesogen moiety.
[0230] 5.2.1 Mono-Functional and Difunctional Monomer Having
Mesogen Moiety
[0231] The mono-functional or difunctional monomer having a mesogen
moiety has no particular limitation in structure, and may be, for
example, the compounds of Formula (M1) or (M2) below.
##STR00083##
[0232] In Formula (M1), R.sup.a is each independently hydrogen,
halogen, --C.ident.N, --N.dbd.C.dbd.O, --N.dbd.C.dbd.S or a
C.sub.1-20 alkyl, in which arbitrary --CH.sub.2 may be substituted
with --O--, --S--, --CO--, --COO--, --OCO--, --CH.dbd.CH--,
--CF.dbd.CF-- or --C.ident.C--, and arbitrary hydrogen in the alkyl
and the alkyl with arbitrary --CH.sub.2-- substituted with --O--,
--S--, --COO--, --OCO--, --CH.dbd.CH--, --CF.dbd.CF-- or
--C.ident.C-- may be substituted with halogen or --C.ident.N.
R.sup.b is each independently a polymerable group of Formulas
(M3-1)-(M3-7).
[0233] R.sup.a is preferably hydrogen, halogen, --C.ident.N,
--CF.sub.3, --CF.sub.2H, --CFH.sub.2, --OCF.sub.3, --OCF.sub.2H, a
C.sub.1-20 alkyl, a C.sub.1-19 alkoxy, a C.sub.2-21 alkenyl, and a
C.sub.2-21 alkynyl. Particularly preferably, R.sup.a is
--C.ident.N, a C.sub.1-20 alkyl, and a C.sub.1-19 alkoxy.
[0234] In Formula (M2), R.sup.b is each independently a polymerable
group of Formulas (M3-1)-(M3-7).
[0235] Herein, in Formulas (M3-1)-(M3-7), R.sup.d is each
independently hydrogen, halogen, or a C.sub.1-5 alkyl, in which
arbitrary hydrogen may be substituted with halogen. R.sup.d is
preferably hydrogen, halogen, and methyl. Particularly preferably,
R.sup.d is hydrogen, fluorine, and methyl.
[0236] Furthermore, Formulas (M3-2), (M3-3), (M3-4), and (M3-7) are
preferably polymerized through free radical polymerization.
Formulas (M3-1), (M3-5), and (M3-6) are preferably polymerized
through cationic polymerization. The polymerizations are both
living polymerization, and thus can be initiated only when a small
amount of free radical or cationic active species is generated in
the reaction system. In order to accelerate the generation of the
active species, a polymerization initiator may be used. Light or
heat may be used to generate the active species.
[0237] In Formulas (M1) and (M2), A.sup.M is each independently an
aromatic or non-aromatic 5- or 6-membered ring, or a fused ring
having 9 or more carbon atoms, in which --CH.sub.2-- in the rings
may be substituted with --O--, --S--, --NH--, or --NCH.sub.3--,
--CH.dbd. in the rings may be substituted with --N.dbd., and
hydrogen atom in the rings may be substituted with halogen, and a
C.sub.1-5 alkyl or haloalkyl. Specific examples of preferred
A.sup.M are 1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene,
naphthalene-2,6-diyl, tetrahydronaphthalene-2,6-diyl,
fluorene-2,7-diyl, or bicyclo[2.2.2]octane-1,4-diyl, in which
arbitrary --CH.sub.2-- in the rings may be substituted with --O--,
arbitrary --CH.dbd. may be substituted with --N.dbd., and arbitrary
hydrogen in the rings and the rings with arbitrary --CH.dbd.
substituted with --CH.dbd. may be substituted with halogen, a
C.sub.1-5 alkyl, or a C.sub.1-5 haloalkyl.
[0238] In consideration of the stability of the compound,
--CH.sub.2--O--CH.sub.2--O-- with oxygen being not adjacent to one
another is preferred to --CH.sub.2--O--O--CH.sub.2-- with oxygen
being adjacent to one another. This also applies to the case of
sulphur.
[0239] Among the groups, especially preferred A.sup.M is
1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene,
2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene,
2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene,
2-methyl-1,4-phenylene, 2-trifluoromethyl-1,4-phenylene,
2,3-bis(trifluoromethyl)-1,4-phenylene, naphthalene-2,6-diyl,
tetrahydronaphthalene-2,6-diyl, fluorene-2,7-diyl,
9-methylfluorene-2,7-diyl, 1,3-dioxane-2,5-diyl, pyridine-2,5-diyl,
and pyrimidine-2,5-diyl. Moreover, as for the stereo configuration
of 1,4-cyclohexylene and 1,3-dioxane-2,5-diyl, trans-configuration
is superior to cis-configuration.
[0240] Because 2-fluoro-1,4-phenylene and 3-fluoro-1,4-phenylene
are identical in structure, the latter is not exemplified. This
also applies to the case of the relationship between
2,5-difluoro-1,4-phenylene and 3,6-difluoro-1,4-phenylene.
[0241] In Formulas (M1) and (M2), Y is each independently a single
bond, or a C.sub.1-20 alkylene, in which arbitrary --CH.sub.2-- may
be substituted with --O--, --S--, --CH.dbd.CH--, --C.ident.C--,
--COO-- or --OCO--. Y is preferably a single bond,
--(CH.sub.2).sub.m2--, --O(CH.sub.2).sub.m2--, and
--(CH.sub.2).sub.m2O-- (where m2 is an integer of 1-20).
Particularly preferably, Y is a single bond, --(CH.sub.2).sub.m2--,
--O(CH.sub.2).sub.m2--, and --(CH.sub.2).sub.m2O-- (where m2 is an
integer of 1-10). In consideration of the stability of the
compound, --Y--R.sup.a and --Y--R.sup.b preferably have no
--O--O--, --O--S--, --S--O--, or --S--S--.
[0242] In Formulas (M1) and (M2), Z.sup.M is each independently a
single bond, --(CH.sub.2).sub.m3--, --O(CH.sub.2).sub.m3--,
--(CH.sub.2).sub.m3O--, --O(CH.sub.2).sub.m3O--, --CH.dbd.CH--,
--C.ident.C--, --COO--, --OCO--, --(CF.sub.2).sub.2--,
--(CH.sub.2).sub.2--COO--, --OCO--(CH.sub.2).sub.2--,
--CH.dbd.CH--COO--, --OCO--CH.dbd.CH--, --C.ident.C--COO--,
--OCO--C.ident.C--, --CH.dbd.CH--(CH.sub.2).sub.2--,
--(CH.sub.2).sub.2--CH.dbd.CH--, --CF.dbd.CF--,
--C.ident.C--CH.dbd.CH--, --CH.dbd.CH--C.ident.C--,
--OCF.sub.2--(CH.sub.2).sub.2--, --(CH.sub.2).sub.2--CF.sub.2O--,
--OCF.sub.2--, or --CF.sub.2O--(where m3 is an integer of
1-20).
[0243] Z.sup.M is preferably a single bond, --(CH.sub.2).sub.m3--,
--O(CH.sub.2).sub.m3--, --(CH.sub.2).sub.m3O--, --CH.dbd.CH--,
--C.ident.C--, --COO--, --OCO--, --(CH.sub.2).sub.2--COO--,
--OCO--(CH.sub.2).sub.2--, --CH.dbd.CH--COO--, --OCO--CH.dbd.CH--,
--OCF.sub.2--, and --CF.sub.2O--.
[0244] In Formulas (M1) and (M2), m1 is an integer of 1-6, and
preferably an integer of 1-3. When m1 is 1, the compound is a
bicyclic compound having two, for example, 6-membered rings. When
m1 is 2 or 3, the compound is a tricyclic or tetracyclic compound,
respectively. For example, when m1 is 1, two A.sup.M may be
identical or different. Furthermore, for example when m1 is 2,
three A.sup.M (or two Z.sup.M) may be identical or different. When
m1 is 3-6, it is also the same case. This also applies to the case
of Ra, Rb, Rd, Z.sup.M, A.sup.M, and Y.
[0245] Even the Compound (M1) of Formula (M1) and the Compound (M2)
of Formula (M2) contains an isotope in an amount higher than its
natural abundance, such as .sup.2H (deuterium) and .sup.13C are
useful, due to the identical properties.
[0246] More preferred examples of Compounds (M1) and (M2) are
Compounds (M1-1)-(M1-41) and (M2-1)-(M2-27) of Formulas
(M1-1)-(M1-41) and (M2-1)-(M2-27). Among the compounds, R.sup.a,
R.sup.b, R.sup.d, Z.sup.M, A.sup.M, Y, and p have the same meaning
as those described for Formulas (M1) and (M2) in the previous
aspects of the present invention.
[0247] Each partial structure of Compounds (M1-1)-(M1-41) and
Compounds (M2-1)-(M2-27) is described as follows. Partial structure
(a1) represents 1,4-phenylene with arbitrary hydrogen substituted
with fluorine. Partial structure (a2) represents 1,4-phenylene in
which arbitrary hydrogen may be substituted with fluorine. Partial
structure (a3) represents 1,4-phenylene in which arbitrary hydrogen
may be substituted with either fluorine or methyl. Partial
structure (a4) represents fluorene in which hydrogen at position 9
may be substituted with methyl.
##STR00084## ##STR00085## ##STR00086## ##STR00087##
##STR00088##
[0248] A polymerizable compound other than the monomer having no
mesogen moiety and the monomers (M1) and (M2) having mesogen moiety
may be used, if desired.
[0249] In order to optimize the optical isotropy of the
polymer/liquid crystal composite material of the present invention,
a monomer having a mesogen moiety and three or more polymerizable
functional groups can also be used. The monomer having a mesogen
moiety and three or more polymerizable functional groups is
preferably a well-know compound, for example, (M4-1)-(M4-3), and
more specifically, the compounds described in Japanese Patent
Publication Nos. 2000-327632, 2004-182949, and 2004-59772. In
(M4-1)-(M4-3), R.sup.b, Za, Y, and (F) have the same meaning as
described above.
##STR00089##
[0250] 5.2.2 Monomer Having No Mesogen Moiety and Having
Polmerizable Functional Group
[0251] Examples of the monomer having no mesogen moiety and having
a polymerizable group are linear or branched acrylate of 1-30
carbons, linear or branched diacrylate of 1-30 carbons, and a
monomer having three or more polymerizable groups, for example, but
not limited to, glycerol-propoxide (1PO/OH) triacrylate,
pentaerythritol-propoxide triacrylate, pentaerythritol triacrylate,
trimethylolpropane-ethoxide triacrylate,
trimethylolpropane-propoxide triacrylate, trimethylolpropane
triacrylate, di(trimethylolpropane) tetraacrylate, pentaerythritol
tetraacrylate, di(pentaerythritol) pentaacrylate,
di(pentaerythritol) hexaacrylate, and trimethylolpropane
triacrylate.
[0252] 5.2.3 Polymerization Initiator
[0253] The polymerization pattern used to produce the polymer
compound for forming the composite material of the present
invention has no particular limitation, and may be, for example,
photo-radical polymerization, thermo-radical polymerization, and
photo-cationic polymerization.
[0254] The photo-radical polymerization initiator useful for
photo-radical polymerization is, for example, DAROCUR.TM. 1173 and
DAROCUR 4265 (both are trade names, from Ciba Specialty Chemicals),
IRGACURE.TM. 184, IRGACURE 369, IRGACURE 500, IRGACURE 651,
IRGACURE 784, IRGACURE 819, IRGACURE 907, IRGACURE 1300, IRGACURE
1700, IRGACURE 1800, IRGACURE 1850, and IRGACURE 2959 (all are
trade names, from Ciba Specialty Chemicals).
[0255] Preferred examples of the thermo-radical polymerization
initiators useful for thermo-radical polymerization are benzoyl
peroxide, diisopropyl peroxydicarbonate, tert-butyl
peroxy(2-ethylhexanoate), tert-butyl peroxypivalate, tert-butyl
peroxydiisobutyrate, lauroyl peroxide, dimethyl
2,2'-azobisisobutyrate (MAIB), di-t-butyl peroxide (DTBPO),
azobisisobutyronitrile (AIBN), and azobiscyclohexanecarbonitrile
(ACN), and the like.
[0256] Examples of the photo-cationic polymerization initiator
useful for photo-cationic polymerization are diaryliodonium salt
(referred to as "DAS", hereafter), and triarylsulfonium salt
(referred to as "TAS", hereafter), and the like.
[0257] Examples of DAS are diphenyliodonium tetrafluoroborate,
diphenyliodonium hexafluorophosphate, diphenyliodonium
hexafluoroarsenate, diphenyliodonium trifluoromesylate,
diphenyliodonium trifluoroacetate, diphenyliodonium
p-toluenesulfonate, diphenyliodonium
tetrakis(pentafluorophenyl)borate, 4-methoxyphenylphenyliodonium
tetrafluoroborate, 4-methoxyphenylphenyliodonium
hexafluorophosphate, 4-methoxyphenylphenyliodonium
hexafluoroarsenate, 4-methoxyphenylphenyliodonium
trifluoromesylate, 4-methoxyphenylphenyliodonium trifluoroacetate,
and 4-methoxyphenylphenyliodonium p-toluenesulfonate.
[0258] DAS may be sensitized by adding a photosensitizer, such as
thioxanthone, phenothiazine, chlorothioxanthone, xanthone,
anthracene, diphenyl anthracene, and rubrene.
[0259] Examples of TAS are triphenylsulfonium tetrafluoroborate,
triphenylsulfonium hexafluorophosphate, triphenylsulfonium
hexafluoroarsenate, triphenylsulfonium trifluoromesylate,
triphenylsulfonium trifluoroacetate, triphenylsulfonium
p-toluenesulfonate, triphenylsulfonium
tetrakis(pentafluorophenyl)borate, 4-methoxyphenyldiphenylsulfonium
tetrafluoroborate, 4-methoxy phenyldiphenylsulfonium
hexafluorophosphate, 4-methoxyphenyldiphenylsulfonium
hexafluoroarsenate, 4-methoxyphenyldiphenylsulfonium
trifluoromesylate, 4-methoxyphenyldiphenylsulfonium
trifluoroacetate, and 4-methoxyphenyldiphenylsulfonium
p-toluenesulfonate, and the like.
[0260] Specific examples of the photo-cationic polymerization
initiator are Cyracure.TM. UVI-6990, Cyracure UVI-6974, and
Cyracure UVI-6992 (all are trade names, from UCC Corporation);
Adeka Optomer SP-150, Adeka Optomer SP-152, Adeka Optomer SP-170,
Adeka Optomer SP-172 (all are trade names, from ADEKA Corporation),
Rhodorsil Photoinitiator 2074 (trade name, from RHODIA JAPAN
Corporation), IRGACURE.TM. 250 (trade name, from Ciba Specialty
Chemicals), and UV-9380C (trade name, from GE TOSHIBA SILICONES Co.
Ltd), and the like.
[0261] 5.2.4 Curing Agents and Others
[0262] In preparing the polymer compound for forming the composite
material of the present invention, in addition to the monomers and
the polymerization initiator above, one or two or more other
preferred components, such as, curing agent, catalyst, and
stabilizer, may also be further added.
[0263] The latent curing agents well-known in the art which are
commonly used as curing agent for epoxy resins may be used.
Examples of the latent curing agent for epoxy resins are
amine-based curing agents, novolac resin-based curing agents,
imidazole-based curing agents, and anhydride-based curing agents,
and the like. Examples of amine-based curing agents are aliphatic
polyamines such as diethylenetriamine, triethylenetetraamine,
tetraethylenepentaamine, m-xylenediamine, trimethyl
hexamethylenediamine, 2-methyl pentamethylenediamine, and
diethylaminopropylamine; alicyclic polyamines such as isophorone
diamine, 1,3-diaminomethylcyclohexane,
bis(4-aminocyclohexyl)methane, norbornanediamine,
1,2-diaminocyclohexane, and Laromin; and aromatic polyamines such
as diaminodiphenylmethane, diaminodiphenylethane, and
m-phenylenediamine.
[0264] Examples of novolac-based curing agents are phenolic novolac
resin, and bisphenolic novolac resin, and the like. Examples of
imidazole-based curing agents are 2-methylimidazole,
2-ethylhexylimidazole, 2-phenylimidazole, and
1-cyanoethyl-2-phenylimidazolium trimellitate, and the like.
[0265] Examples of anhydride-based curing agents are
tetrahydrophthalic anhydride, hexahydrophthalic anhydride,
methyltetrahydrophthalic anhydride, methylhexahydrophthalic
anhydride, methylcyclohexene tetracarboxylic dianhydride, phthalic
anhydride, trimellitic anhydride, pyromellitic dianhydride, and
benzophenone tetracarboxylic dianhydride, and the like.
[0266] Furthermore, a curing accelerator may further be used to
facilitate the curing reaction of a polymerizable compound with
glycidyl, epoxy, or oxetanyl and the curing agent. Examples of the
curing accelerator are tertiary amines such as benzyldimethylamine,
tris(dimethylaminomethyl)phenol, and dimethylcyclohexylamine;
imidazoles such as 1-cyanoethyl-2-ethyl-4-methylimidazole, and
2-ethyl-4-methylimidazole; organophosphorus compounds such as
triphenylphosphine; quaternary phosphosium salts such as
tetraphenylphosphosium bromide; diazobicyclo alkenes such as
1,8-diazobicyclo[5.4.0]undecene-7 or an organic acid salt thereof;
quaternary ammonium salts such as tetraethylammonium bromide, and
tetrabutylammonium bromide; boron compounds such as boron
trifluoride, and triphenyl borate, and the like. These curing
accelerators may be used alone, or in a combination of two or
more.
[0267] Moreover, a stabilizer is preferably added, for example, to
prevent unwanted polymerization during storage. The stabilizer may
be any compound well known to those of ordinary skill in the art,
representative examples of which are 4-ethoxyphenol, hydroquinone,
and butylated hydroxytoluene (BHT), and the like.
[0268] 5.3 Content of Liquid Crystal Composition
[0269] The content of the liquid crystal composition in the
polymer/liquid crystal composite material of the present invention
is preferably as high as possible, so long as it is within a range
in which the composite material exhibits an optically isotropic
liquid crystal phase. The reason lies in the fact that the higher
the content of the liquid crystal composition is, the greater the
electric birefringence value of the composite material of the
present invention is.
[0270] In the polymer/liquid crystal composite material of the
present invention, the content of the liquid crystal composition is
preferably 60-99 wt %, more preferably 60-95 wt %, and particularly
preferably 65-95 wt %, with respect to the composite material. The
content of the polymer is preferably 1-40 wt %, more preferably
5-40 wt %, and particularly preferably 5-35 wt %, with respect to
the composite material.
[0271] 5.4 Other Components
[0272] The polymer/liquid crystal composite material of the present
invention may also contain, for example, a dichroic dye and a
photochromic compound, without prejudice to the effect of the
present invention.
[0273] The present invention is further described in detail with
reference to examples; however, the present invention is not
limited to thereto. Furthermore, "%" denotes "wt %", unless
specifically indicated.
[0274] 6 Optical Device
[0275] A sixth aspect of the present invention is an optical
device, which contains the liquid crystal composition or the
polymer/liquid crystal composite material (hereafter, both are
sometimes collectively referred to as liquid crystal medium) and is
driven in an optically isotropic liquid crystal phase.
[0276] The liquid crystal medium is optically isotropic in the
absence of an electric field and exhibits an optical anisotropy in
the presence of an electric field, such that optical modulation may
be achieved with an electric field.
[0277] As an example of the structure of the LCD device, as shown
in FIG. 1, the electrodes on the comb-like electrode substrate have
such a structure that Electrode 1 extending from the left side and
Electrode 2 extending from the right side are alternatively
arranged. When a potential difference exists between Electrode 1
and Electrode 2, the comb-like electrode substrate is provided with
an electric field in two directions (upward and downward), as shown
in FIG. 1.
EXAMPLES
[0278] The resulting compound is characterized by a nuclear
magnetic resonance (NMR) spectrum obtained by .sup.1H-NMR analysis
and a gas chromatogram obtained by gas chromatography (GC)
analysis. The analysis methods are firstly illustrated below.
[0279] .sup.1H-NMR analysis: .sup.1H-NMR analysis was carried out
by using DRX-500 (manufactured by Bruker BioSpin Co., Ltd). In the
measurement, a sample prepared in an embodiment was dissolved in a
deuterated solvent, such as CDCl.sub.3, which is capable of
dissolving the sample, and then was measured with a NMR apparatus
at 500 MHz at room temperature in 24 times of accumulation. In the
resulting NMR spectrum, s denotes singlet, d denotes doublet, t
denotes triplet, q denotes quartet, and m denotes multiplet.
Furthermore, tetramethylsilane (TMS) was used as the standard of
chemical shift .delta. of zero.
[0280] GC analysis: GC analysis was carried out by using a GC
apparatus Model GC-14B (manufactured by Shimazu). The column was
the capillary column CBP1-M25-025 (length 25=m, inner diameter=0.22
mm, film thickness=0.25 .mu.m, manufactured by Shimazu); and the
stationary liquid phase was polydimethylsiloxane (non-polarity).
The carrier gas was helium, and the flow rate was adjusted to 1
ml/min. The sample evaporation chamber was set at 300.degree. C.,
and the detector (flame ionization detector, FID) was set at
300.degree. C.
[0281] A sample was dissolved in toluene to give a solution of 1 wt
%, and then 1 .mu.l of the solution was injected into the sample
evaporation chamber.
[0282] The recorder used was Chromatopac Model C-R6A (manufactured
by Shimazu) or an equivalent thereof. The obtained gas chromatogram
exhibited peak retention times and peak areas corresponding to the
component compounds.
[0283] In addition, the solvent for diluting the sample was, for
example, chloroform or hexane. The column used was, for example,
capillary column DB-1 (length=30 m, inner diameter=0.32 mm, film
thickness=0.25 m, manufactured by Agilent Technologies Inc.), HP-1
(length=30 m, inner diameter=0.32 mm, film thickness=0.25 .mu.m.,
manufactured by Agilent Technologies Inc.), Rtx-1 (length=30 m,
inner diameter=0.32 mm, film thickness=0.25 .mu.m, manufactured by
Restek Corporation), or BP-1 (length=30 m, inner diameter=0.32 mm,
film thickness=0.25 .mu.m, manufactured by SGE International Pty.
Ltd.).
[0284] The area ratios of the peaks in the gas chromatogram
correspond to the ratios of the component compounds. Generally, the
weight percentages of the component compounds in the analyzed
sample are not completely identical to the area percentages of the
peaks. However, in the present invention, when the columns
described above are used, the correction coefficient is
substantially 1. Therefore, the weight percentages of the component
compounds in the analyzed sample are substantially corresponding to
the area percentages of the peaks. The reason lies in that there is
no significant difference among the correction coefficients of the
component compounds. In order to more accurately calculate the
ratios of the liquid crystal compounds in the liquid crystal
composition with GC, the internal standard method for GC may be
used. GC measurements were simultaneously performed on an
accurately weighed specified amount of a liquid crystal compound
component (detected component) and a liquid crystal compound as
standard (standard), and the relative intensity was previously
calculated as peak area ratio of the detected component to the
standard. If a correction was performed by using the relative
intensity expressed as peak area ratio of each component to the
standard, the ratios of the liquid crystal compounds in the liquid
crystal composition can be more accurately calculated with GC
analysis.
[0285] Samples for Determining Characteristic Values of Liquid
Crystal Compounds
[0286] Two methods may be used to measure the characteristic values
of a liquid crystal compound, i.e., taking a pure compound as a
sample, and mixing a compound in a mother liquid crystal to form a
sample.
[0287] When a sample prepared by mixing a compound with a mother
liquid crystal is used, the following method is used for the
measurement. Firstly, 15 wt % of the resulting liquid crystal
compound was mixed with 85 wt % of the mother liquid crystal to
prepare a sample, and then an extrapolated value is calculated from
the measured value of the sample according to the extrapolation
method based on the equation below, as the characteristic value of
the compound.
[Extrapolated Value]=(100.times.[measured value of the sample]-[wt
% of the mother liquid crystal].times.[measured value of the mother
liquid crystal])/[wt % of the liquid crystal compound]
[0288] While a smectic phase or crystal may be precipitated at the
above ratio of the liquid crystal compound and the mother liquid
crystal at 25.degree. C., the ratio of the liquid crystal compound
and the mother liquid crystal is changed to be 10 wt %:90 wt %, 5
wt %:95 wt %, 1 wt %:99 wt % in order. The composition without
separation of a smectic phase or crystal at 25.degree. C. was
measured for the characteristic value of the samples, and the
characteristic values of the liquid crystal compound is calculated
through extrapolation based on above equation.
[0289] There are numerous mother liquid crystals that may be used
for the measurement. For example, the composition of the mother
liquid crystal A is as follows (wt %).
[0290] Mother Liquid Crystal A:
##STR00090##
[0291] Method for Measuring Characteristic Values of Liquid Crystal
Compounds
[0292] The measurement of the characteristic values was carried out
with the methods below. These methods are mainly those described in
EIAJ.cndot.ED-2521A of the Standard of Electric Industries
Association of Japan, or modifications of the same. Moreover, the
TN device used in the measurement was not equipped with TFT.
[0293] With respect to the determined values, in case that the
liquid crystal compound itself is used as a sample, the obtained
values are recorded as experimental data; and in case that a
mixture of the liquid crystal compound and a mother liquid crystal
is used as a sample, the extrapolated values obtained with the
extrapolation method are recorded as experimental data.
[0294] The phase structure and the phase transition temperature
(.degree. C.) were measured by using the methods (1) and (2)
below.
[0295] (1) A compound was placed on a hot plate (Hot Stage, Model
FP-52, manufactured by Mettler, Corp.) in a melting point measuring
apparatus equipped with a polarizing microscope, and the phase
behaviour and its change were observed by the polarizing microscope
while the sample was heated at a rate of 3.degree. C./min, to
determine the type of the liquid crystal phase.
[0296] (2) A scanning calorimetry DSC-7 system or Diamond DSC
system (manufactured by PerkinElmer Corp.) was used, at a heating
or cooling rate of 3.degree. C./min, and the on set of the
endothermic peak or the exothermic peak along with the phase change
of the sample was calculated with the extrapolation method, to
determine the phase transition temperature.
[0297] Hereafter, a crystal is represented by K, and for
differentiation, two crystals are represented by K.sub.1 or
K.sub.2, respectively. A smectic phase is represented by Sm, a
nematic phase is represented by N, and a liquid (isotropic phase)
is represented by I. For differentiation, a smectic B phase and a
smectic A phase in the smectic phase are represented by SmB and
SmA, respectively. BP represents a blue phase or an optically
isotropic liquid crystal phase. A biphase coexistence is sometimes
represented by (N*+I) or (N*+BP). Specifically, (N*+I) represents a
phase in which a non-liquid crystal isotropic phase and a chiral
nematic phase coexist, and (N*+BP) represents a phase in which a BP
phase or an optically isotropic liquid crystal phase and a chiral
nematic phase coexist. Un represents a non-optically isotropic
unidentified phase. For the expression of the phase transition
temperature, for example, "K 50.0 N 100.0 I" means that the phase
transition temperature (KN) from the crystal to the nematic phase
is 50.0.degree. C., and the phase transition temperature (NI) from
the nematic phase to the liquid is 100.0.degree. C. This also
applies to the case of other expressions.
[0298] Upper-limit temperature of a nematic phase (T.sub.NI,
.degree. C.): a sample (a mixture of a liquid crystal compound and
a mother liquid crystal) was placed on a hot plate (Hot Stage,
Model FP-52, manufactured by Mettler Corp.) in a melting point
measuring apparatus equipped with a polarizing microscope, and was
observed with the polarizing microscope while the sample was heated
at a rate of 1.degree. C./min. The temperature at which a part of
the sample began to change from a nematic phase into an isotropic
liquid was recorded as the upper-limit temperature of the nematic
phase, sometimes abbreviated as "upper-limit temperature"
hereafter.
[0299] Low-temperature compatibility: samples were prepared by
mixing a mother liquid crystal with a liquid crystal compound in
such a manner that the content of the latter was 20 wt %, 15 wt %,
10 wt %, 5 wt %, 3 wt %, and 1 wt %, respectively, and then placed
into glass bottles. The glass bottles were kept in a freezer at
-10.degree. C. or -20.degree. C. for a specified period of time,
and the presence or absence of a crystal or a smectic phase was
observed.
[0300] Viscosity (.eta., determined at 20.degree. C., mPas): the
viscosity of a mixture of a liquid crystal compound and a mother
liquid crystal is measured with an E-type rotational
viscometer.
[0301] Refractive index anisotropy (.DELTA.n): the measurement was
carried out at 25.degree. C. by using light having a wavelength of
589 nm, with an Abbe refractometer having a polarizing plate
mounted on an ocular lens. After the surface of the main prism is
rubbed in a direction, a sample (a mixture of a liquid crystal
compound and a mother liquid crystal) was dripped onto the main
prism. The refractive index (n.sub.//) was determined when the
polarizing direction was paralleled to the rubbing direction, and
the refractive index (n.sub..perp.) was determined when the
polarizing direction was perpendicular to the rubbing direction.
The value of refractive index anisotropy (.DELTA.n) was calculated
according to the equation .DELTA.n=n.sub.//-n.sub..perp..
[0302] Dielectric anisotropy (.DELTA..di-elect cons.: determined at
25.degree. C.): a sample (a mixture of a liquid crystal compound
and a mother liquid crystal) was fed into a liquid crystal cell
with a distance (cell gap) of about 9 .mu.m between two glass
substrates and a twist angle of 80 degrees. The liquid crystal cell
was applied with a voltage of 20 V and the dielectric constant
(.di-elect cons..sub.//) in the major-axis direction of the liquid
crystal molecule was determined. Then, a voltage of 0.5 V was
applied and the dielectric constant (.di-elect cons..sub..perp.) in
the minor axis direction of the liquid crystal molecule was
determined. The value of dielectric anisotropy was calculated
according to the equation .DELTA..di-elect cons.=.di-elect
cons..sub.//-.di-elect cons..sub..perp..
[0303] Pitch (P; determined at 25.degree. C., m)
[0304] A pitch length was measured through selective reflection
(Handbook of Liquid Crystal, p 196, 2000, Maruzen). For the
selective reflection wavelength .lamda., the relationship
<n>p/.lamda.=1 exists. Here, <n> denotes the average
refractive index, and is calculated according to the equation
<n>={(n.sub.//.sup.2+n.sub..perp..sup.2)/2}.sup.1/2. The
selective reflection wavelength was determined by a
microspectrophotometer (Trade name MSV-350, manufactured by Japan
Electronics Co., Ltd.). The pitch was calculated by dividing the
resulting reflection wavelength by the average refractive index.
When the concentration of the optically active compound is low, the
pitch of a cholesteric liquid crystal having a reflection
wavelength in a region of wavelength longer than that of visible
light is proportional to the reciprocal of the concentration.
Therefore, multiple points were measured for the pitch length of
the liquid crystal having a selective reflection wavelength in the
visible light region, and then the pitch was calculated by using a
linear extrapolation method. The "optically active compound" is
equivalent to the chiral reagent in the present invention.
Synthesis Example 1
Synthesis of Formula (S1-8)
##STR00091##
[0306] The synthesis scheme is as shown below.
##STR00092##
[0307] Synthesis of Compound (S1-2)
[0308] 88.3 g (S1-1), 7.54 g catalyst, and 900 ml tetrahydrofuran
(THF) were charged into a reactor under a nitrogen atmosphere, and
2 mol/L solution of butylmagnesium chloride in THF was added
dropwise at room temperature, and refluxed for 4 h. The reaction
solution was cooled to room temperature, which was added with
toluene, and then washed with 1 N hydrochloric acid and water.
After drying over magnesium sulfate, the solvent was removed under
vacuum. After chromatography on silica gel column with heptane as a
developing solvent, and drying under vacuum, 75.7 g (S1-2) was
obtained. The yield of (S1-2) obtained from (S1-1) is 93.1%.
[0309] Synthesis of Compound (S1-3)
[0310] 55.5 g (S1-2) and 550 ml THF were charged into a reactor
under a nitrogen atmosphere, and cooled to -70.degree. C., and then
161 ml n-BuLi (1.55 M; solution in n-hexane) was added dropwise and
stirred for 1 hr at -70.degree. C. 450 ml solution of 63.4 g iodine
in THF was added dropwise to the reaction solution at -70.degree.
C., and stirred for 5 h. The reaction solution was warmed to room
temperature, and then poured into a solution of sodium thiosulfate
in water. The product was extracted with ethyl acetate, and then
the organic layer was washed with an aqueous sodium thiosulfate
solution and water. After drying over magnesium sulfate, the
solvent was removed through distillation under vacuum. After
chromatography on silica gel column with heptane/toluene=3/1 as a
developing solvent, and drying under vacuum, 79.1 g (S1-3) was
obtained. The yield of (S1-3) obtained from (S1-2) is 97.5%.
[0311] Synthesis of Compound (S1-5)
[0312] 79.1 g (S1-3), 38.4 g 3,5-difluorophenylboronic acid (S1-4),
3.5 g tetrakis(triphenylphosphine)palladium, 70.9 g sodium
carbonate, and 560 ml mixed solvent of toluene/ethanol/water=3/3/1
(volume ratio) were charged into a reactor under a nitrogen
atmosphere, and refluxed for 7 h. The reaction solution was cooled
to room temperature, which was added with toluene, and then washed
with 1 N hydrochloric acid and water. After drying over magnesium
sulfate, the solvent was removed through distillation under vacuum.
After chromatography on silica gel column with heptane as a
developing solvent, drying under vacuum, and recrystallization of
the remaining component in a mixed solvent of ethanol/ethyl
acetate=4/1, 50.6 g (S1-5) was obtained. The yield of (S1-5)
obtained from (S1-3) is 66.2%.
[0313] Synthesis of Compound (S1-6)
[0314] 15.0 g Compound (S1-5) and 150 ml THF were charged into a
reactor under a nitrogen atmosphere, and then cooled to -74.degree.
C. 27.4 ml 1.60 M n-butyl lithium solution in n-hexane was added
dropwise at a temperature in a range of -74.degree. C. to
-60.degree. C., and then further stirred for 60 min. Then, 20.0 ml
solution of 12.6 g dibromodifluoromethane in THF was added dropwise
at a temperature in a range of -75.degree. C. to -70.degree.,
warmed back to 25.degree. C., and stirred for 60 min. The resulting
reaction mixture was poured into 150 ml ice water, and mixed. 100
ml toluene was added, to form an organic layer and an aqueous layer
separated from each other, and the resulting organic layer was
obtained through extraction, which was washed with brine, and dried
over anhydrous magnesium sulfate. The resulting solution was
concentrated under vacuum, and the residue was purified by
chromatography on silica gel column with heptane as a developing
solvent. After removal of the solvent through distillation, and
drying, 16.5 g (S1-6) was obtained.
[0315] Synthesis of Compound (S1-8)
[0316] 6.0 g Compound (S1-6), 1.4 g 3,4,5-trifluorophenol (S1-7),
2.8 g potassium carbonate, 100 ml N,N-dimethylformamide (DMF) were
charged into a reactor under a nitrogen atmosphere, and stirred for
120 min at 90.degree. C. After the temperature of the reaction
mixture was returned back to 25.degree. C., the reaction mixture
was then poured into 50 ml ice water and mixed. 100 ml toluene was
added, to form an organic layer and an aqueous layer separated from
each other, and the resulting organic layer was obtained through
extraction, which was then washed with a saturated aqueous sodium
bicarbonate solution, 0.5 N aqueous sodium hydroxide solution, and
saline in sequence, and dried over anhydrous magnesium sulfate. The
resulting solution was concentrated under vacuum, and the residue
was purified by chromatography on silica gel column with heptane as
a developing solvent. Then, after purification through
recrystallization in a mixed solvent of heptane/Solmix A-11 and
drying, 1.7 g (S1-8) was obtained. The yield of (S1-8) obtained
from (S1-5) is 20.4%.
[0317] The phase transition temperature of the resulting Compound
(S1-8) is as follows.
[0318] Phase transition temperature (.degree. C.): K 92.4 N 95.4
I.
[0319] The resulting compound was identified to be (S1-9) through
the following chemical shift .delta. (ppm) obtained with
.sup.1H-NMR analysis using CDCL.sub.3 as solvent. Chemical shift
.delta. (ppm): 7.36 (t, 1H), 7.26-7.20 (m, 4H), 7.08 (d, 1H),
7.04-6.99 (m, 3H), 2.67 (t, 2H), 1.67-1.64 (m, 2H), 1.41-1.37 (m,
2H), 0.96 (t, 3H).
[0320] Physical Properties of Liquid Crystal Compound (S1-8)
[0321] The four compounds designated as mother liquid crystal A
above were mixed, to prepare a mother liquid crystal A having a
nematic phase. The physical properties of the mother liquid crystal
A are as follows.
[0322] Upper-limit temperature (T.sub.NI)=71.7.degree. C.;
dielectric anisotropy (.DELTA..di-elect cons.)=11.0; and refractive
index anisotropy (.DELTA.n)=0.137.
[0323] Liquid Crystal Composition B containing 90 wt % of the
mother liquid crystal A and 10 wt % of (S1-8) obtained in Synthesis
Example 1 was prepared. The characteristic values of the resultant
Liquid Crystal Composition B were determined. The extrapolated
characteristic values of Liquid Crystal Compound (S1-8) calculated
based on the measurements through extrapolation are as follows.
[0324] Upper-limit temperature (T.sub.NI)=54.7.degree. C.;
dielectric anisotropy (.DELTA..di-elect cons.)=54.2; and refractive
index anisotropy (.DELTA.n)=0.167.
It can be known from the results that, Liquid Crystal Compound
(S1-8) has a large dielectric anisotropy (.DELTA..di-elect cons.),
and refractive index anisotropy (.DELTA.n).
Synthesis Examples 2-4
Synthesis of (S2-1), (S3-1), and (S4-1)
##STR00093##
[0326] The unit of the phase transition temperature is .degree.
C.
[0327] Synthesis of Compounds (S2-1), (S3-1), and (S4-1)
[0328] The compounds are synthesized with suitable reagents
following the method of Synthesis Example 1.
[0329] Physical Properties of Liquid Crystal Compound (S2-1)
[0330] The four compounds designated as mother liquid crystal A
above were mixed, to prepare a mother liquid crystal A having a
nematic phase. The physical properties of the mother liquid crystal
A are as follows.
[0331] Upper-limit temperature (T.sub.NI)=71.7.degree. C.;
dielectric anisotropy (.DELTA..di-elect cons.)=11.0; and refractive
index anisotropy (.DELTA.n)=0.137.
[0332] Liquid Crystal Composition C containing 90 wt % of the
mother liquid crystal A and 10 wt % of (S2-1) obtained in Synthesis
Example 2 was prepared. The characteristic values of the resultant
Liquid Crystal Composition C were determined. The extrapolated
characteristic values of the Liquid Crystal Compound (S2-1)
calculated based on the measurements through extrapolation are as
follows.
[0333] Upper-limit temperature (T.sub.NI)=61.7.degree. C.;
dielectric anisotropy (.DELTA..di-elect cons.)=51.1; and refractive
index anisotropy (.DELTA.n)=0.177.
[0334] It can be known from the results that Liquid Crystal
Compound (S2-1) has a large dielectric anisotropy (.DELTA..di-elect
cons.) and refractive index anisotropy (.DELTA.n).
[0335] Physical Properties of Liquid Crystal Compound (S3-1)
[0336] Liquid Crystal Composition D containing 95 wt % of the
mother liquid crystal A and 5 wt % of (S3-1) obtained in Synthesis
Example 2 was prepared. The characteristic values of the resultant
Liquid Crystal Composition C were determined. The extrapolated
characteristic values of Liquid Crystal Compound (S3-1) calculated
based on the measurements through extrapolation are as follows.
[0337] Upper-limit temperature (T.sub.NI)=55.7.degree. C.;
dielectric anisotropy (.DELTA..di-elect cons.)=68.1; and refractive
index anisotropy (.DELTA.n)=0.177.
[0338] It can be known from the results that Liquid Crystal
Compound (S3-1) has a very large dielectric anisotropy
(.DELTA..di-elect cons.).
[0339] Physical Properties of Liquid Crystal Compound (S4-1)
[0340] Liquid Crystal Composition E containing 90 wt % of the
mother liquid crystal A and 10 wt % of (S4-1) obtained in Synthesis
Example 2 was prepared. The characteristic values of the resultant
Liquid Crystal Composition E were determined. The extrapolated
characteristic values of the Liquid Crystal Compound (S4-1)
calculated based on the measurements through extrapolation are as
follows.
[0341] Upper-limit temperature (T.sub.NI)=59.7.degree. C.;
dielectric anisotropy (.DELTA..di-elect cons.)=65.9; and refractive
index anisotropy (.DELTA.n)=0.167.
[0342] It can be known from the results that Liquid Crystal
Compound (S4-1) has a very large dielectric anisotropy
(.DELTA..di-elect cons.).
Synthesis Example 5
Synthesis of (S5-3)
##STR00094##
[0344] The synthesis scheme is as shown below.
##STR00095##
[0345] Synthesis of Compound (S5-3)
[0346] Synthesis of (S5-1) from (S1-2) is achieved following the
method for synthesizing (S1-6) from (S1-5) in Synthesis Example 1,
in which (S1-2) is used in place of (S1-5). Synthesis of (S5-3)
from (S5-1) is achieved following the method for synthesizing
(S1-8) from (S1-6) in Synthesis Example 1, in which (S5-1) is used
in place of (S1-6), and (S5-2) is used in place of (S1-7). The
phase transition temperature of the resultant compound (S5-3) is as
follows.
[0347] Phase transition temperature (.degree. C.): K 63.1N 88.5
I.
[0348] Physical Properties of Liquid Crystal Compound (S5-3)
[0349] Liquid Crystal Composition F containing 85 wt % of the
mother liquid crystal A and 15 wt % of (S5-3) obtained in Synthesis
Example 5 was prepared. The characteristic values of the resultant
Liquid Crystal Composition F were determined. The extrapolated
characteristic values of the Liquid Crystal Compound (S5-3)
calculated based on the measurements through extrapolation are as
follows.
[0350] Upper-limit temperature (T.sub.NI)=55.7.degree. C.;
dielectric anisotropy (.DELTA..di-elect cons.)=42.1; and refractive
index anisotropy (.DELTA.n)=0.164.
[0351] It can be known from the results that Liquid Crystal
Compound (S5-3) has good compatibility with other liquid crystal
compounds, and has a large dielectric anisotropy (.DELTA..di-elect
cons.), and refractive index anisotropy (.DELTA.n).
Synthesis Example 6
Synthesis of (S6-1)
##STR00096##
[0353] Synthesis of Compound (S6-1)
[0354] (S6-1) is synthesized following the method for synthesizing
(S5-3) in Synthesis Example 5.
[0355] Physical Properties of Liquid Crystal Compound (S6-1)
[0356] Liquid Crystal Composition G containing 85 wt % of the
mother liquid crystal A and 15 wt % of (S6-1) obtained in Synthesis
Example 6 was prepared. The characteristic values of the resultant
Liquid Crystal Composition G were determined. The extrapolated
characteristic values of the Liquid Crystal Compound (S6-2)
calculated based on the measurements through extrapolation are as
follows.
[0357] Upper-limit temperature (T.sub.NI)=51.0.degree. C.;
dielectric anisotropy (.DELTA..di-elect cons.)=43.4; and refractive
index anisotropy (.DELTA.n)=0.164.
[0358] It can be known from the results that Liquid Crystal
Compound (S6-1) has good compatibility with other liquid crystal
compounds, and has a large dielectric anisotropy (.DELTA..di-elect
cons.) and refractive index anisotropy (.DELTA.n).
[0359] (Composition of the Present Invention)
[0360] In the present invention, the characteristic values of the
liquid crystal compositions were measured following the methods
below. The methods are mainly those described in
EIAJ.cndot.ED-2521A of the Standard of Electric Industries
Association of Japan or modifications of the same. The TN device
used in the measurement was not equipped with TFT.
[0361] Upper-limit temperature of a nematic phase (NI, .degree.
C.): a sample was placed on a hot plate in a melting point
measuring apparatus equipped with a polarizing microscope, and
heated at a rate of 1.degree. C./min. The temperature at which a
part of the sample began to change from a nematic phase into an
isotropic liquid was recorded as the upper-limit temperature of the
nematic phase, which is sometimes abbreviated as "upper-limit
temperature".
[0362] Lower-limit temperature of a nematic phase (T.sub.C,
.degree. C.): a sample having a nematic phase was kept in a freezer
at 0.degree. C., -10.degree. C., -20.degree. C., -30.degree. C.,
and -40.degree. C. for 10 days, and observed for the liquid crystal
phase. For example, in a case where the sample exhibits a nematic
phase at -20.degree. C., and is changed to a crystal or a smectic
phase at -30.degree. C., the T.sub.C is recorded as
.ltoreq.-20.degree. C. The lower-limit temperature of a nematic
phase is sometimes abbreviated as "lower-limit temperature".
[0363] Transition temperature of an optically isotropic liquid
crystal phase: a sample was placed on a hot plate in a melting
point measuring apparatus equipped with a polarizing microscope,
and in a crossed nicols state, initially heated to a temperature
allowing the sample to change into a non-liquid crystal isotropic
phase, and then cooled at a rate of 1.degree. C./min until a chiral
nematic phase or an optically isotropic liquid crystal phase was
completely formed. The phase transition temperature during this
cooling process was measured. Then, the temperature was raised at a
rate of 1.degree. C./min, and the phase transition temperature
during this heating process was measured. In the present invention,
unless specifically indicated, the phase transition temperature in
the heating process was recorded as the phase transition
temperature. Where it was difficult to determine the phase
transition temperature of the optically isotropic liquid crystal
phase in a dark field under crossed nicols, the phase transition
temperature could be determined after the polarizing plate is
deviated from the crossed polarization state by 1-10 degrees.
[0364] Viscosity (.eta., determined at 20.degree. C., mPas): the
viscosity was measured with an E-type rotational viscometer.
[0365] Rotational viscosity (.gamma.1, determined at 25.degree. C.,
mPas):
[0366] 1) For a sample with a positive dielectric anisotropy: the
measurement was carried out following the method described in M.
Imai et al., Molecular Crystals and Liquid Crystals, Vol. 259, 37
(1995). The sample was placed into a TN device with a twist angle
of 0 degree and a distance (cell gap) of 5 .mu.m between two glass
substrates. The TN device was applied with a voltage in a range of
16 to 19.5 V stepwise by 0.5 V. After a period of 0.2 s without
voltage application a voltage application was repeated with a
rectangular wave (rectangular pulse of 0.2 s), followed by a period
of 2 s without voltage application. The peak current and the peak
time of the transient current resulted from the application of the
voltage were measured. Then, the value of rotational viscosity was
calculated according to the measurements and the Equation (8)
described on page 40 of the paper of M. Imai et al. The dielectric
anisotropy value required for this calculation was obtained by
using the device used in the measurement of the rotational
viscosity, following the method for determining dielectric
anisotropy below.
[0367] For a sample with a negative dielectric anisotropy: the
measurement was carried out following the method described in M.
Imai et al., Molecular Crystals and Liquid Crystals, Vol. 259, 37
(1995). The sample was placed into a vertical alignment (VA) device
with a distance (cell gap) of 20 .mu.m between two glass
substrates. The device was applied with a voltage in a range of 30
to 50 V stepwise by 1 V. After a period of 0.2 s without voltage
application, a voltage application was repeated with a rectangular
wave (rectangular pulse of 0.2 s) followed by a period of 2 s
without voltage application. The peak current and the peak time of
the transient current resulted from the application of the voltage
were measured. Then, the value of rotational viscosity was
calculated according to the measurements and the Equation (8)
described on page of the paper of M. Imai et al. The dielectric
anisotropy value required for this calculation was obtained by
using the method for determining dielectric anisotropy below.
[0368] Refractive index anisotropy (.DELTA.n, determined at
25.degree. C.): the measurement was carried out by using light
having a wavelength of 589 nm, with an Abbe refractometer having a
polarizing plate mounted on the ocular lens. After the surface of
the main prism was rubbed in a direction, the sample was dropped
onto the main prism. The refractive index (n.sub.//) was determined
when the polarizing direction was paralleled to the rubbing
direction, and the refractive index (n.sub..perp.) was determined
when the polarizing direction was perpendicular to the rubbing
direction. The value of refractive index anisotropy was calculated
according the equation .DELTA.n=n.sub.//-n.sub..perp.. When the
sample was a composition, the process could be used to determine
the refractive index anisotropy. When the sample was a compound,
the compound was mixed with a suitable composition for determining
the refractive index anisotropy. In this case, the refractive index
anisotropy value of the compound was an extrapolated value.
[0369] Dielectric anisotropy (.DELTA..di-elect cons., determined at
25.degree. C.): when the sample was a compound, the compound was
mixed with a suitable composition for determining the dielectric
anisotropy. In this case, the dielectric anisotropy value of the
compound was an extrapolated value.
[0370] 1) For a composition with a positive dielectric anisotropy:
a sample was placed into a liquid crystal cell with a distance
(gap) of about 9 .mu.m between two glass substrates and a twist
angle of 80 degrees. The liquid crystal cell was applied with a
voltage of 20 V to determine the dielectric constant (.di-elect
cons..sub.//) in the major axis direction of the liquid crystal
molecule. Then, a voltage of 0.5 V was applied to determine the
dielectric constant (.di-elect cons..sub..perp.) in the minor axis
direction of the liquid crystal molecule. The value of dielectric
anisotropy was calculated according to the equation
.DELTA..di-elect cons.=.di-elect cons..sub.//-.di-elect
cons..sub..perp..
[0371] 2) For a composition with a negative dielectric anisotropy:
a sample was placed into a liquid crystal cell which was processed
into a homeotropic alignment, and a voltage of 0.5 v was applied to
determine the dielectric constant (.di-elect cons..sub.//). Then,
the sample was placed into a liquid crystal cell which was
processed into a homogeneous alignment, and a voltage of 0.5 v was
applied to determine the dielectric constant (.di-elect
cons..sub..perp.). The value of dielectric anisotropy was
calculated according to the equation .DELTA..di-elect
cons.=.di-elect cons..sub.//-.di-elect cons..sub..perp..
[0372] Threshold voltage (Vth, determined at 25.degree. C., V):
when the sample was a compound, the compound was mixed with a
suitable composition for determining the threshold voltage. In this
case, the threshold voltage value of the compound was an
extrapolated value. 1) For a composition with a positive dielectric
anisotropy: a sample was placed into an LCD device of a normally
white mode with a distance (gap) of (0.5/.DELTA.n) .mu.m between
two glass substrates and a twist angle of 80 degrees, in which
.DELTA.n was the value of refractive index anisotropy determined by
using the method above. A rectangular wave with a frequency of 32
Hz was applied to the device. Then, the voltage of the rectangular
wave was increased, and the voltage value at which the
transmittance of light through the device reached 90% was
determined.
[0373] 2) For a composition with a negative dielectric anisotropy:
a sample was placed into an LCD device of a normally black mode
with a distance (gap) of about 9 .mu.m between two glass
substrates, which was processed into a homeotropic alignment. A
rectangular wave with a frequency of 32 Hz was applied to the
device. Then, the voltage of the rectangular wave was increased,
and the voltage value at which the transmittance of light through
the device reached 10% was determined.
[0374] Voltage holding ratio (VHR, determined at 25.degree. C., %):
the TN device used for the determination had a polyimide alignment
film and a distance (cell gap) of 6 .mu.m between two glass
substrates. A sample was placed into the device, which was then
sealed with a UV-polymerizable adhesive. Then, the TN device was
charged by applying a pulse voltage (5V, 60 ms). The voltage decay
was determined by using a high-speed voltmeter at an interval of
16.7 ms, and the area A between the voltage curve and the
horizontal axis per unit cycle was calculated. The area B was an
area where no decay occurs. The voltage holding ratio was the
percentage of the area A relative to the area B.
[0375] Helical pitch (determined at 20.degree. C., .mu.m): The
helical pitch was measured according to the wedge cell method of
Grandjean-Cano. A sample was injected into a wedge cell of
Grandjean-Cano, and then the distance (a, in .mu.m) between the
disclination lines observed from the wedge cell was measured. The
helical pitch (p) could be calculated according to the equation
p=2atan .theta., in which .theta. is the angle between the two
glass plates in the wedge cell.
[0376] Alternatively, the pitch length can be determined with
selective reflection (Handbook of Liquid Crystal, p 196, issued in
2000, by Maruzen). For the selective reflection wavelength .lamda.,
the relationship <n>p/.lamda.=1 exists, where <n>
denotes the average refractive index, and can be calculated with
the equation
<n>={(m.sub.//.sup.2+n.sub..perp..sup.2)/2}.sup.1/2. The
selective reflection wavelength was determined with a
microspectrophotometer (trade name MSV-350, manufactured by Japan
Electronics Co., Ltd). The pitch was obtained by dividing the
resulting reflection wavelength by the average refractive
index.
[0377] When the concentration of the chiral reagent is low, the
pitch of the cholesteric liquid crystal having a reflection
wavelength in a region of wavelength longer than that of visible
light is proportional to the reciprocal of the concentration.
Therefore, multiple points were measured for the helical pitch
length of the liquid crystal having a selective reflection
wavelength in the visible light region, and the helical pitch was
calculated by using a linear extrapolation method.
[0378] The proportion (percentage) of a component or a liquid
crystal compound is weight percentage (wt %) based on the total
weight of the liquid crystal compounds. The composition can be
prepared by mixing the components including liquid crystal
compounds after being weighed. Thus, the wt % of each component can
be easily calculated.
Example 1
[0379] Liquid Crystal Composition A was prepared by mixing the
liquid crystal compounds shown below at the following ratios.
[0380] Corresponding general formulas are shown at the right sides
of the structural formulas.
[0381] Liquid Crystal Composition A
##STR00097## ##STR00098##
[0382] Then, Liquid Crystal Composition B containing Liquid Crystal
Composition A (94 wt %) and a chiral reagent ISO-60BA2 (6 wt %) of
the formula below was obtained.
[0383] In addition, ISO-60BA2 was obtained by esterifying
isosorbide and 4-hexyloxybenzoic acid in the presence of
dicyclohexyl Carbodiimide (DCC), and 4-dimethylpyridine.
##STR00099##
Example 2
Preparation of Mixture of Monomer and Liquid Crystal
Composition
[0384] As a mixture of a monomer and a liquid crystal composition,
Liquid Crystal Composition C-M was prepared by mixing 79.4 wt %
liquid crystal composition B, 10.0 wt % n-dodecyl acrylate, 10.0 wt
% 1,4-di(4-(6-(acryloxy)hexyloxy)benzoyloxy)-2-toluene, and 0.6 wt
% 2,2'-dimethoxybenzylacetophenone as a photo polymerization
initiator.
[0385] Preparation of Polymer/Liquid Crystal Composite Material
[0386] Liquid Crystal Composition C-M was held between a
non-aligned comb-like electrode substrate and a glass substrate
(without electrode) opposite to the comb-like electrode substrate
with a cell thickness of 10 .mu.m, and then the resulting liquid
crystal cell was heated to 63.0.degree. C. In this state, the cell
was irradiated with UV light of 365 nm at an intensity of 23
mWcm.sup.-2 for 1 min for polymerization.
[0387] The polymer/liquid crystal composite material C-P thus
prepared could maintain an optically isotropic liquid crystal phase
even being cooled to room temperature.
[0388] Furthermore, as shown in FIG. 1, the electrodes on the
comb-like electrode substrate have such a structure that Electrode
1 extending from the left side and Electrode 2 extending from the
right side are alternatively arranged. Thus, when a potential
difference exists between Electrode 1 and Electrode 2, the
comb-like electrode substrate can be provided with an electric
field in two directions (upward and downward), as shown in FIG.
1.
Example 3
[0389] A liquid crystal cell holding the polymer/liquid crystal
composite material C-1P obtained in Example 2 was disposed in the
optical system of FIG. 2 to measure the electro-optic properties,
as follows. Using the white light source of a polarizing microscope
(ECLIPSE LV100POL, manufactured by Nikon) as a light source, the
incident light from the white light source irradiated on the liquid
crystal cell was perpendicular to the liquid crystal cell plane,
and the line direction of the comb-like electrode was at 45 degrees
with respect to the polarizer and the analyzer respectively. The
relationship between the applied voltage and the transmittance was
investigated by setting the measuring temperature at the clearing
point (59.1.degree. C.)-40.degree. C. =19.1.degree. C. If a
rectangular wave of 47.6 V was applied, then the transmittance was
up to 80%, and the transmitted light intensity was saturated.
Example 4
[0390] Liquid Crystal Composition D was prepared by mixing the
liquid crystal compounds shown below at the following ratios.
[0391] Corresponding general formulas are shown at the right sides
of the structural formulas.
[0392] Liquid Crystal Composition D
##STR00100## ##STR00101##
[0393] Then, Liquid Crystal Composition E containing Liquid Crystal
Composition D (94 wt %) and a chiral reagent 2 (6.1 wt %) of the
formula below was obtained.
[0394] Structural Formula of Chiral Reagent 2
##STR00102##
Example 5
Preparation of Mixture of Monomer and Liquid Crystal
Composition
[0395] As a mixture of a monomer and a liquid crystal composition,
Liquid Crystal Compositions F-M were prepared by mixing 87.4 wt %
Liquid Crystal Composition E, 6.0 wt % n-dodecyl acrylate, 6.0 wt %
1,4-di(4-(6-(acryloxy)propoxy)benzoyloxy)-2-toluene, and 0.6 wt %
2,2'-dimethoxybenzylacetophenone as a photo polymerization
initiator.
[0396] Preparation of Polymer/Liquid Crystal Composite Material
[0397] Liquid Crystal Compositions F-M were held between a
non-aligned comb-like electrode substrate and an glass substrate
(without electrode) opposite to the comb-like electrode substrate
with a cell thickness of 10 .mu.m, and then the resulting liquid
crystal cell was heated to 77.0.degree. C. In this state, the cell
was irradiated with UV light of 365 nm at an intensity of 23
mWcm.sup.-2 for 1 min for polymerization.
[0398] The polymer/liquid crystal composite material F--P thus
prepared could maintain an optically isotropic liquid crystal phase
even being cooled to room temperature.
[0399] Furthermore, as shown in FIG. 1, the electrodes on the
comb-like electrode substrate have such a structure that Electrode
1 extending from the left side and Electrode 2 extending from the
right side are alternatively arranged. Thus, when a potential
difference exists between Electrode 1 and Electrode 2, the
comb-like electrode substrate can be provided with an electric
field in two directions (upward and downward), as shown in FIG.
1.
Example 6
[0400] A liquid crystal cell holding the polymer/liquid crystal
composite material F-P obtained in Example 5 was disposed in the
optical system of FIG. 2 to measure the electro-optic properties,
as follows. Using the white light source of a polarizing microscope
(ECLIPSE LV100POL, manufactured by Nikon) as a light source, the
incident light from the white light source irradiated on the liquid
crystal cell was perpendicular to the liquid crystal cell plane,
and the line direction of the comb-like electrode was at 45 degrees
with respect to the polarizer and the analyzer respectively. The
relationship between the applied voltage and the transmittance was
investigated by setting the measuring temperature at the clearing
point of Liquid Crystal Composition E (64.9.degree. C.)-25.degree.
C.=39.9.degree. C. If a rectangular wave of 58 V was applied, then
the transmittance was up to 80%, and the transmitted light
intensity was saturated.
Example 7
[0401] Liquid Crystal Composition G was prepared by mixing Liquid
Crystal Composition D and Liquid Crystal Compound (16-16a) below at
a weight ratio of 85/15.
##STR00103##
[0402] Then, Liquid Crystal Composition H containing Liquid Crystal
Composition G (94 wt %) and the chiral reagent 2 (7.0 wt %) was
obtained.
Example 8
Preparation of Mixture of Monomer and Liquid Crystal
Composition
[0403] As a mixture of a monomer and a liquid crystal composition,
Liquid Crystal Composition I-M was prepared by mixing 87.4 wt %
Liquid Crystal Composition H, 6.0 wt % n-dodecyl acrylate, 6.0 wt %
1,4-di(4-(6-(acryloxy)propoxy)benzoyloxy)-2-toluene, and 0.6 wt %
2,2'-dimethoxybenzylacetophenone as a photo polymerization
initiator.
[0404] Preparation of Polymer/Liquid Crystal Composite Material
[0405] Liquid Crystal Composition I-M was held between a
non-aligned comb-like electrode substrate and an opposite glass
substrate (without electrode) opposite to the comb-like electrode
substrate with a cell thickness of 10 .mu.m, and then the resulting
liquid crystal cell was heated to 60.0.degree. C. In this state,
the cell was irradiated with UV light of 365 nm at an intensity of
23 mWcm.sup.-2 for 1 min for polymerization.
[0406] The polymer/liquid crystal composite material I-P thus
prepared could maintain an optically isotropic liquid crystal phase
even being cooled to room temperature.
[0407] Furthermore, as shown in FIG. 1, the electrodes on the
comb-like electrode substrate have such a structure that Electrode
1 extending from the left side and Electrode 2 extending from the
right side are alternatively arranged. Thus, when a potential
difference exists between Electrode 1 and Electrode 2, the
comb-like electrode substrate can be provided with an electric
field in two directions (upward and downward), as shown in FIG.
1.
Example 9
[0408] A liquid crystal cell holding the polymer/liquid crystal
composite material I-P obtained in Example 8 was disposed in the
optical system of FIG. 2 to measure the electro-optic properties,
as follows. Using the white light source of a polarizing microscope
(ECLIPSE LV100POL, manufactured by Nikon) as a light source, the
incident light from the white light source irradiated on the liquid
crystal cell was perpendicular to the liquid crystal cell plane,
and the line direction of the comb-like electrode was at 45 degrees
with respect to the polarizer and the analyzer respectively. The
relationship between the applied voltage and the transmittance was
investigated by setting the measuring temperature at the clearing
point of Liquid Crystal Composition H (57.1.degree. C.)-25.degree.
C.=32.1.degree. C. If a rectangular wave of 58 V was applied, then
the transmittance was up to 80%, and the transmitted light
intensity was saturated.
APPLICABILITY IN INDUSTRY
[0409] The present invention is applicable, for example, in the
field of optical devices, such as display devices using a liquid
crystal medium.
* * * * *